If an invalid date shows up in a mediapackage when indexing, it throws an exception and the item is skipped with no identifying information about the mediapackage.
These should be caught and logged properly so the item can get indexed and there is enough info in the logs to find the issue and fix the data.
Merged in smarquard/matterhorn/t/MH-12059-fix-invalid-dates-indexing (pull request #1368) commit f36b5bc