Autos are weird like that sometimes.. different genetics and/or different environmental factors can cause for a later flower trigger.
It is possible you have a photoperiod gene that got thru. The nature of the autoflowering trait is that it’s recessive, and if these companies don’t put in the time to work thru several generations before releasing the beans - you can have the occasional photoperiod get thru.
That said, mephisto and Humboldt are reputable breeders, so I’d bet that’s not the case. But something to keep in mind. If it doesn’t trigger in another couple weeks, that is likely the culprit