WTF? runOnce throws TimeoutException

Here’s my log:

12:30:38 AM PST: error java.util.concurrent.TimeoutException: Execution time exceeded 20 app execution seconds @ line 146
12:30:26 AM PST: trace Scheduling 'taskNotify' for InstalledSmartApp: xxxx
12:30:14 AM PST: trace Deleting scheduled job 'taskNotify' for InstalledSmartApp: xxxx

The line 146 is this:

runOnce(date, taskNotify)

Apparently, it takes SlowThings more than 12 seconds to delete schedules job and another 12 seconds to schedule it, which exceed 20 seconds execution limit and causes timeout exception. This happens intermittently. Sometimes it works, sometimes it doesn’t.

Generally, everything seems to be running painfully slow.