diff --git a/src/db/gpx.ts b/src/db/gpx.ts
index c90d966..d712ad0 100644
--- a/src/db/gpx.ts
+++ b/src/db/gpx.ts
@@ -1,4 +1,4 @@
-import { cloneDeep } from 'lodash';
+import { cloneDeep, isEmpty } from 'lodash';
 import { PureComponent } from 'react';
 import { $DEVCOMP } from 'solid-js';
 import { Point, Rectangle } from '../components/map/types';
@@ -111,12 +111,15 @@ const prune = (
             ...extensions,
             ...subObjects[index].extensions,
           };
+          if (isEmpty(subObjects[index].extensions)) {
+            subObjects[index].extensions = undefined;
+          }
           docs.push({
             _id: getUri(key, subId),
             type: key,
             doc: subObjects[index],
           });
-          prune(subId, subObjects[index], previousGpx, extensions, docs);
+          prune(subId, subObjects[index], previousGpx, {}, docs);
         }
         object[key] = undefined;
       } else prune(id, object[key], previousGpx, extensions, docs);