So sorry to hear about the issue you are having after updating. I haven’t been able to reproduce this behavior yet. Are you able to send a link to the test sheet where you are seeing this?
My first thought is perhaps there is an issue with something within the theme. Perhaps even an old Sign-up Sheet template override that for some reason is conflicting with the latest version? If you created any template overrides in your theme they would have “dlssus” or “fdsus” in the file name or directory in your theme.
You can also test by switching to a default WordPress theme (such as Twenty Twenty) and see if the issue remains.