We are having the same issue. We updated to The Events Calendar 4.5.10 and The Events Calendar: Community Events 4.5.4 and the community events add page was all wonky. Non of the java worked.
We rolled back both file sets to the previous version and things worked fine. Then we updated just community events, and there were no issues. So the issue seems to be in the update of The Events Calendar 4.5.10. So my advice, stay or roll back to 4.5.9 and you should be good till they resolve the issue.