It's almost certainly an add-on cron, but it's very hard to debug. You can try running them individually to see if it triggers anything, but it might not - it really depends how they might work. At that point, you mostly just need to contact the author. 1.2.1 does try to add fatal error logging which might help confirm that the error is happening but depending on where the error happens, it might be hard to identify which task specifically is triggering the problem.
The problem is likely not 1.2 specific. It just manifests itself in a different way due to system changes.