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.