diff --git a/imports/startup/server/subsUnion.js b/imports/startup/server/subsUnion.js
index 5828dc2..641b308 100644
--- a/imports/startup/server/subsUnion.js
+++ b/imports/startup/server/subsUnion.js
@@ -41,48 +41,50 @@ Meteor.startup(async () => {
     return valid;
   };
 
+  // Only called once calcUnionAsync has actually resolved — union === null here
+  // means "zero valid subscriptions", a real result, not a failed computation.
+  // (A prior version guarded this with `typeof union === 'object'`, which is
+  // true for null too, so a failed worker call — caught upstream, leaving
+  // union as null — looked identical to a legitimate empty union and got
+  // silently stored as "null". Callers must catch calcUnionAsync failures
+  // themselves and skip calling this, instead of relying on this check.)
   const storeUnion = async (isPublic, union, count) => {
     const publicl = isPublic ? 'public' : 'private';
     const Publicl = publicl.replace(/\b\w/g, l => l.toUpperCase());
-
-    if (typeof union === 'object') {
-      const bounds = union === null ? null : L.geoJSON(union).getBounds();
-      const unionSet = {
-        $set: {
-          name: `subs-${publicl}-union`,
-          value: JSON.stringify(union),
-          isPublic,
-          description: `${Publicl} subscriptions union`,
-          type: 'string'
-        }
-      };
-      const boundsSet = {
-        $set: {
-          name: `subs-${publicl}-union-bounds`,
-          value: JSON.stringify(bounds),
-          isPublic,
-          description: `${Publicl} subscriptions union bounds`,
-          type: 'string'
-        }
-      };
-      const sizeSet = {
-        $set: {
-          name: 'subs-union-count',
-          value: count,
-          isPublic: false,
-          description: 'Subscriptions count',
-          type: 'number'
-        }
-      };
-      // FIXME, take care of object size:
-      // https://stackoverflow.com/questions/10827812/what-is-the-length-maximum-for-a-string-data-type-in-mongodb-used-with-ruby
-      await SiteSettings.upsertAsync({ name: `subs-${publicl}-union` }, unionSet, { multi: false });
-      await SiteSettings.upsertAsync({ name: `subs-${publicl}-union-bounds` }, boundsSet, { multi: false });
-      await SiteSettings.upsertAsync({ name: 'subs-union-count' }, sizeSet, { multi: false });
-      if (debug) console.log(`${Publicl} subscription union calculated`);
-    } else {
-      console.log('Subscription union failed!');
-    }
+    const bounds = union === null ? null : L.geoJSON(union).getBounds();
+    const unionSet = {
+      $set: {
+        name: `subs-${publicl}-union`,
+        value: JSON.stringify(union),
+        isPublic,
+        description: `${Publicl} subscriptions union`,
+        type: 'string'
+      }
+    };
+    const boundsSet = {
+      $set: {
+        name: `subs-${publicl}-union-bounds`,
+        value: JSON.stringify(bounds),
+        isPublic,
+        description: `${Publicl} subscriptions union bounds`,
+        type: 'string'
+      }
+    };
+    const sizeSet = {
+      $set: {
+        name: 'subs-union-count',
+        value: count,
+        isPublic: false,
+        description: 'Subscriptions count',
+        type: 'number'
+      }
+    };
+    // FIXME, take care of object size:
+    // https://stackoverflow.com/questions/10827812/what-is-the-length-maximum-for-a-string-data-type-in-mongodb-used-with-ruby
+    await SiteSettings.upsertAsync({ name: `subs-${publicl}-union` }, unionSet, { multi: false });
+    await SiteSettings.upsertAsync({ name: `subs-${publicl}-union-bounds` }, boundsSet, { multi: false });
+    await SiteSettings.upsertAsync({ name: 'subs-union-count' }, sizeSet, { multi: false });
+    if (debug) console.log(`${Publicl} subscription union calculated`);
   };
 
   const process = async (isPublic) => {
@@ -90,13 +92,12 @@ Meteor.startup(async () => {
     const decorate = isPublic ? addNoisy : noNoisy;
     const decorated = subscribers.filter(isValidSub).map(decorate);
 
-    let union = null;
     try {
-      union = await calcUnionAsync(decorated);
+      const union = await calcUnionAsync(decorated);
+      await storeUnion(isPublic, union, subscribers.length);
     } catch (e) {
-      console.error('subsUnion worker failed', e);
+      console.error('subsUnion worker failed, union left unchanged', e);
     }
-    await storeUnion(isPublic, union, subscribers.length);
   };
 
   const recreate = async () => { await process(true); await process(false); };
@@ -138,17 +139,16 @@ Meteor.startup(async () => {
       const current = await SiteSettings.findOneAsync({ name: `subs-${publicl}-union` });
       const baseUnion = current && current.value ? JSON.parse(current.value) : null;
 
-      let union = null;
       try {
         // eslint-disable-next-line no-await-in-loop
-        union = await calcUnionAsync([decorated], baseUnion);
+        const union = await calcUnionAsync([decorated], baseUnion);
+        // eslint-disable-next-line no-await-in-loop
+        await storeUnion(isPublic, union, countSubs);
       } catch (e) {
         console.error('subsUnion incremental worker failed, falling back to a full recreate', e);
         recomputePending = true;
         return;
       }
-      // eslint-disable-next-line no-await-in-loop
-      await storeUnion(isPublic, union, countSubs);
     }
     if (debug) console.log('Subs union updated incrementally');
   };