Can't remove a node #2009

Summary

1. Go to the root tree page and remove a node
2. A success notification is displayed but /sync call is not performed (not even after waiting much longer than in the recording attached)
3. After the page reload, the node is back and /sync is broken for all upcoming calls (500, MultipleObjectsReturned at /api/sync/get() returned more than one ContentNode -- it returned 2!)

(The node seems to be deleted after removing IndexedDB and reloading the page one more time)

Tested with clear IndexedDB state.