diff --git a/.last-branch b/.last-branch
index 5e9dd4a..7273c0f 100644
--- a/.last-branch
+++ b/.last-branch
@@ -1 +1 @@
-v20260320-02-cove-historical-runs-and-detail
+25
diff --git a/containers/backupchecks/src/backend/app/main/routes_shared.py b/containers/backupchecks/src/backend/app/main/routes_shared.py
index 95c54ba..1e52727 100644
--- a/containers/backupchecks/src/backend/app/main/routes_shared.py
+++ b/containers/backupchecks/src/backend/app/main/routes_shared.py
@@ -659,7 +659,9 @@ def _infer_schedule_map_from_runs(job_id: int):
     - Synthetic missed rows never influence schedule inference.
     - To reduce noise, a weekday/time bucket must occur at least MIN_OCCURRENCES times.
     """
-    MIN_OCCURRENCES = 3
+    # Higher threshold reduces false positives from short-lived patterns
+    # (e.g. a time-of-day shift that briefly leaves two active slots).
+    MIN_OCCURRENCES = 5
     schedule = {i: [] for i in range(7)}  # 0=Mon .. 6=Sun
 
     # Certain job types are informational and should never participate in schedule
@@ -691,6 +693,10 @@ def _infer_schedule_map_from_runs(job_id: int):
     try:
         # Only infer schedules from real runs that came from mail reports.
         # Synthetic "Missed" rows must never influence schedule inference.
+        # Limit to the last 90 days so that schedule changes (different day,
+        # time, or frequency) take effect quickly and do not leave stale slots
+        # generating false missed runs.
+        cutoff_utc = datetime.utcnow() - timedelta(days=90)
         runs = (
             JobRun.query
             .filter(
@@ -698,6 +704,7 @@ def _infer_schedule_map_from_runs(job_id: int):
                 JobRun.run_at.isnot(None),
                 JobRun.missed.is_(False),
                 JobRun.mail_message_id.isnot(None),
+                JobRun.run_at >= cutoff_utc,
             )
             .order_by(JobRun.run_at.desc())
             .limit(500)
@@ -716,6 +723,7 @@ def _infer_schedule_map_from_runs(job_id: int):
         tz = None
 
     counts = {i: {} for i in range(7)}  # weekday -> { "HH:MM": count }
+    run_dts = []  # Collected for cadence guard below
     for r in runs:
         if not r.run_at:
             continue
@@ -730,12 +738,32 @@ def _infer_schedule_map_from_runs(job_id: int):
             except Exception:
                 pass
 
+        run_dts.append(dt)
         wd = dt.weekday()
         minute_bucket = (dt.minute // 15) * 15
         hh = dt.hour
         tstr = f"{hh:02d}:{minute_bucket:02d}"
         counts[wd][tstr] = int(counts[wd].get(tstr, 0)) + 1
 
+    # Cadence guard: if the median gap between runs is >= 20 days the job has a
+    # monthly (or lower) cadence.  Return an empty weekly schedule so that
+    # _infer_monthly_schedule_from_runs() handles it instead.
+    if len(run_dts) >= 2:
+        sorted_dts = sorted(run_dts)
+        gaps = []
+        for i in range(1, len(sorted_dts)):
+            try:
+                delta_days = (sorted_dts[i] - sorted_dts[i - 1]).total_seconds() / 86400.0
+                if delta_days > 0:
+                    gaps.append(delta_days)
+            except Exception:
+                continue
+        if gaps:
+            gaps_sorted = sorted(gaps)
+            median_gap = gaps_sorted[len(gaps_sorted) // 2]
+            if median_gap >= 20.0:
+                return schedule  # empty — defer to monthly inference
+
     for wd in range(7):
         # Keep only buckets that occur frequently enough.
         keep = [t for t, c in counts[wd].items() if int(c) >= MIN_OCCURRENCES]
@@ -762,6 +790,9 @@ def _infer_monthly_schedule_from_runs(job_id: int):
 
     try:
         # Same "real run" rule as weekly inference.
+        # 180 days gives ~6 occurrences for a monthly job (enough for
+        # MIN_OCCURRENCES=3) while still discarding stale schedule data.
+        cutoff_utc = datetime.utcnow() - timedelta(days=180)
         runs = (
             JobRun.query
             .filter(
@@ -769,6 +800,7 @@ def _infer_monthly_schedule_from_runs(job_id: int):
                 JobRun.run_at.isnot(None),
                 JobRun.missed.is_(False),
                 JobRun.mail_message_id.isnot(None),
+                JobRun.run_at >= cutoff_utc,
             )
             .order_by(JobRun.run_at.asc())
             .limit(500)
diff --git a/containers/backupchecks/src/templates/main/job_detail.html b/containers/backupchecks/src/templates/main/job_detail.html
index 4aa39fc..2053417 100644
--- a/containers/backupchecks/src/templates/main/job_detail.html
+++ b/containers/backupchecks/src/templates/main/job_detail.html
@@ -645,8 +645,8 @@ function renderObjects(objects) {
       function objectSeverityRank(o) {
         var st = String((o && o.status) || "").trim().toLowerCase();
         var err = String((o && o.error_message) || "").trim();
-        if (st === "error" || st === "failed" || st === "failure" || err) return 0;
-        if (st === "warning") return 1;
+        if (st === "error" || st === "failed" || st === "failure") return 0;
+        if (st === "warning" || err) return 1;
         return 2;
       }
 
diff --git a/containers/backupchecks/src/templates/main/run_checks.html b/containers/backupchecks/src/templates/main/run_checks.html
index 3876893..eaa1e62 100644
--- a/containers/backupchecks/src/templates/main/run_checks.html
+++ b/containers/backupchecks/src/templates/main/run_checks.html
@@ -208,17 +208,21 @@
     overflow: auto;
   }
 
-  #runChecksModal #rcm_body_iframe {
-    flex: 1 1 auto;
-    min-height: 0;
-    height: auto;
-  }
   #runChecksModal .rcm-mail-panel {
     display: flex;
     flex-direction: column;
     flex: 1 1 auto;
     min-height: 0;
   }
+  #runChecksModal #rcm_mail_iframe_body {
+    flex: 1 1 auto;
+    min-height: 0;
+    overflow: hidden;
+  }
+  #runChecksModal #rcm_body_iframe {
+    height: 100%;
+    display: block;
+  }
   #runChecksModal .rcm-objects-scroll {
     max-height: 25vh;
     overflow: auto;
@@ -493,8 +497,8 @@ function statusClass(status) {
     function objectSeverityRank(o) {
       var st = String((o && o.status) || '').trim().toLowerCase();
       var err = String((o && o.error_message) || '').trim();
-      if (st === 'error' || st === 'failed' || st === 'failure' || err) return 0;
-      if (st === 'warning') return 1;
+      if (st === 'error' || st === 'failed' || st === 'failure') return 0;
+      if (st === 'warning' || err) return 1;
       return 2;
     }
 
diff --git a/docs/changelog-claude.md b/docs/changelog-claude.md
index e9e6249..b3391f9 100644
--- a/docs/changelog-claude.md
+++ b/docs/changelog-claude.md
@@ -2,6 +2,26 @@
 
 This file documents all changes made to this project via Claude Code.
 
+## [2026-03-20] (6)
+
+### Fixed
+- Run Checks and Job Detail modals — objects list sorting:
+  - `objectSeverityRank`: Warning items with an `error_message` (e.g. "Processing mailbox: MT completed with warning: Cannot process") were incorrectly ranked as Critical (rank 0) due to `|| err` on the rank-0 check; they are now correctly ranked as Warning (rank 1); only status `error`/`failed`/`failure` triggers rank 0
+  - Success objects that do have an `error_message` are still promoted to Warning rank (rank 1) to keep them visible
+- Run Checks modal — mail iframe no longer collapses to near-zero height:
+  - `#rcm_mail_iframe_body` was missing flex rules so the `flex: 1 1 auto` on `#rcm_body_iframe` had no effect (the iframe is not a direct flex child of `.rcm-mail-panel`)
+  - Fixed: `#rcm_mail_iframe_body` now gets `flex: 1 1 auto; min-height: 0; overflow: hidden` so it fills the available panel space; `#rcm_body_iframe` gets `height: 100%; display: block`
+
+## [2026-03-20] (5)
+
+### Fixed
+- Missed run detection: false positives caused by stale schedule data:
+  - **Time-of-day changes**: old time slot stayed active until 500 historical runs were "used up"; now weekly inference only looks at the last 90 days, so a changed run time no longer generates missed runs on the old slot after 90 days
+  - **Frequency changes** (e.g. daily → weekly): same 90-day window ensures old patterns stop influencing inference within 3 months
+  - **Monthly jobs falsely detected as weekly**: after ~21 months a monthly job at a fixed time accumulated 3+ hits per weekday, triggering daily missed runs; fixed by a cadence guard — if the median gap between runs ≥ 20 days, weekly inference is skipped and monthly inference handles the job instead
+  - **Monthly inference**: limited to the last 180 days so schedule changes are forgotten within 6 months while still providing enough data (≥ 3 occurrences) for detection
+  - `MIN_OCCURRENCES` for weekly inference raised from 3 → 5 to reduce false positives from transitional patterns (two overlapping slots during a time shift)
+
 ## [2026-03-20] (4)
 
 ### Added