Right now, if Monitor Mode it enabled, and yet the Latest Time is in the past, it is still re-queued:
Plan XXX has Monitor Mode. Time to resubmit it.
And then later it fails (again) with
Plan XXX couldn't be run before latest time, failed.
I think it's better to leave the Plan Completed or Failed for the last day it was really run under Monitor Mode. Log the fact that it has monitor mode, but that could NOT be honored due to the Latest Time having been passed. This will always give the user a logged reason for the Plan not running. It is not really an error so it is informational and should not cause the Plan to appear failed.