Yeah, I can compile the project in V14 as well. I can not change any F-blocks that are in the project library. Just tested with a new block, aren't able to add a new block to the library either.
Seems we have found a bug.. Co-worker brought this up today, already talking to Siemens who are checking.
Edit: Just tested if I can change and compile an F-FB. I can still do that. The problem lies in releasing it to the library. Project library that is.