diff --git a/ui/src/views/Forecast.jsx b/ui/src/views/Forecast.jsx
index 59e8d0f..1530b5c 100644
--- a/ui/src/views/Forecast.jsx
+++ b/ui/src/views/Forecast.jsx
@@ -933,12 +933,24 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
   }
 
   async function syncOrderExpressions() {
+    dbgOrder('enter')
     const viewer = viewerRef.current
-    if (!viewer) return
+    if (!viewer) { dbgOrder('exit: no viewer'); return }
     const version = versions.find(v => String(v.id) === String(versionId))
     const wanted = buildOrderExpressions(version?.bucket_order, logMeta)
+    dbgOrder('inputs', {
+      versionId,
+      versionFound: !!version,
+      bucket_order: version?.bucket_order ?? null,
+      logMetaCount: Object.keys(logMeta || {}).length,
+      seqs: Object.entries(logMeta || {})
+        .filter(([, m]) => m.seq != null)
+        .map(([id, m]) => `${id}=${m.seq}`),
+      wanted: Object.keys(wanted),
+    })
 
     const { table: _t, ...cfg } = await viewer.save()
+    dbgOrder('saved config read', { existing: Object.keys(cfg.expressions || {}) })
     const current = cfg.expressions || {}
     const managed = Object.values(ORDER_EXPR_NAMES)
 
@@ -958,8 +970,10 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
             .map(([id, m]) => `${id}:${m.tag || m.note}=${m.seq}`),
         })
       }
+      else dbgOrder('exit: already applied', Object.keys(next))
       return
     }
+    dbgOrder('applying', Object.keys(next))
 
     // An expression the pivot is using cannot simply vanish; drop it from the
     // axes first or restore() rejects the config.