I just ran into this one with 9.24.2. In my case the snippet contains a checkbox with an on-change event handler that causes the issue.
Remove the event handler and start the app (start is probably obsolete here). Then add the event handler again and it works again.
Or upgrade to 9.24.5. This is from the 9.24.5 release notes:
There have been some fixes related to snippets in 9.24.2 and 9.24.3. See the release notes. They do not describe your exact problem, but give it a go. Download 9.24.3 and see if this bug is gone.
If not, than see if you can reproduce this error in a new project. If so, open a ticket at support.mendix.com, providing them your test-project. They will likely fix this problem.