Metaslider no longer saving captions

The issue can be found here: https://isoh.org/double-requiem-in-munich-1972-2022/
It works with other themes: Haven’t Tried
It works when I disable all other plugins: Haven’t Tried
Meta Slider version: 3.27.10

My manually entered captions are not being saved when I save the new slide show. They are simply erased by Metaslider. Tried reentering them and then saving … same result, the captions disappear. No problem with all the other slide shows for this site which are all correctly displaying the captions. The most recent one that is still working was saved 2 days ago, so the problem is VERY recent. I have made no changes to the settings.

The page I need help with: [log in to see the link]