I was having this problem as well. No idea what was causing it but I wanted to see if it was a plugin issue so I turned restricted mode on (i.e. disabled all plugins at once). This solved the problem and I could open the problematic files. I then turned off restricted mode as I was going to start debugging the plugins one by one and amazingly the problematic files open with all plugins enabled. So yeah - try turning it off and on
Disabling āDrag-n-Drop for blocksā fixed it for me too, good catch.
I stopped using that plugin a few weeks ago anyways because itās easier to just put a footnote tag ( Thereās a page in the sandbox help vault called Footnote that explains it ) at the end of bulleted lines to embed them in other notes by doing ![[note-name#^flag-name]]. You donāt have to actually add a footnote entry elsewhere in the document to be able to embed them like this. Also, the square brackets seem to be optional when using them like this.