This termbase has been created with an older version of MultiTerm and needs to be updated. This can take several minutes. Continue opening termbases?

I have just downloaded and installed the LATEST versions of Studio and Multiterm and I'm having the following problem with Multiterm.

Whenever I'm working on a project with a term base loaded, it works fine for some time. Then, at some point, the term base disconnects from the project and its terms no longer appear in the Term panel. When I open the project settings, the error mentioned in the post title pops up (framed as a question). If I click "yes", it keeps popping up, now framed as an error. I can't do anything from then on apart from removing the term base, closing the project, reopening the project and loading again the term base. Until it all happens again at some random moment.

My software is up to date:

SDL Trados Studio 2021 SR1 -

SDL MultiTerm 2021 SR1 -

I also tried to uninstall, reload it and install it again. 

Note that this also happens with termbases built with this very Multiterm version.

Thank you for your help.