Active Time Limit Notifications Not Working

I have my son's devices setup on a profile that notifies me when internet activity reaches a certain threshold.  In recent weeks, I receive these notifications early in the morning (5:30am) even though I have bedtime hours set during this time.  When I check activity for his devices overnight, there is zero activity showing during the time the notification says he was active.  Has anyone else experienced this?  Any resolutions?