Rigs made in TBH17 not working in TBH20/22

Hello,
We are working on a project that was started in TBH17, and we wanted to use rigs that were created back in that version. At the same time it is important for us to use TBH20/22 to animate. The drawings we used for the rigs were adobe illustrator files imported to toon boom through the library.

When we try to open those rigs in TBH20/22 some of them work just fine, other show “unable to open” error with every drawing and they don’t show up at all in openGL and in Soft Render, some of them only show some of the drawings. The elements folder looks fine for all of them as far as I can tell.

What do you think might be the issue and can we fix it without rebuilding the rigs?

Best Regards,
Mari