We've found a few examples of tasks going well over their max run time recently. For example, this task had a max run time of 600 seconds (10 minutes). The first attempt ran for 21 minutes, after which it was killed with signal -15. The second run ran for 16 minutes and completed successfully.
It's possible the first one was killed for going over the max run time -- but even if that's the case, that's far too late.