Notion broke my synced blocks, how can I fix them?

If synced blocks stop updating or appear broken, open one of the blocks and check whether it still shows the synced block border and the "Editing in … pages" indicator.

If it doesn't, the block may have been unsynced, so recreate the synced block from the original or copy the original synced block into the required location again.

If other people can't see or edit a synced block, verify they have access to the page containing the original block, since permissions are inherited from the original.

Avoid deleting the original synced block or using Unsync all, especially if the block has more than 10 copies, because this can remove all synced instances.

These are key fixes that we can offer. If you have more, please share.