Hello,
I believe this has only started happening after the latest patch: When in the Magical Library there is one chest on a platform which you can reach via a ladder (it's the last chest you can access before going to the runes "puzzle", not the one where you have to run around the upper outer edges of the scenario) and this time when clicking the ladder the character just stood there doing nothing (tried with multiple characters and after quick saving, quick loading), clicking on the platform above just said no path to destination.
I believe this has started happening since the last patch because this is my second playthrough and didn't have any issue in my first one.
Same thing happened to me since the last patch. Only chest I couldn't get to in the Library.
-Glimpse