the length of the light pollution during dark hours is the concern... interrupting darkness is a problem... a momentary flash is no big deal but prolonged exposure to light is definitely a concern for screwing with hormonal balance required for bloom phase.
this sounds like the lights didn't turn on and it got extra hours of darkness? If so, that is no big deal.. definitely won't cause hermies... it may have slowed down development but only slightly.. 1 day our of many and only a few hours at that is not a major loss of energy relative to the total.
uninterrupted darkness is a key... it is related to a hormonal feedback loop that signals when to switch to growing flowers instead of stems and leaves. it is a "switch' in the plant... interruptions late into flower are less of a problem than early on. if early, you are at higher risk the plant starts to Re-vege or pop nanners later. realize that if somethign does cause nanners, it will take weeks from the cause of the problem to see them -- it takes time to grow, they don't pop out overnight.
That's probably why you get a certain portion that simply don't believe light pollution is a problem.. these ppl are simply wrong. this is old and thoroughly proven knowledge .. nothng new. certainly isn't relegated to marijuana plants. many work this same exact way..
also, it's 10+ hours that will generally flower a plant. "12" is to cover for any oddball genetics. even 13on/11off is perfectly safe to use. i'd avoid the "10hour" for previously listed reason. by using 13/11 you need about 8% fewer photons to provide same DLI.