Oooh that's interesting (although not too much fun if you're training your pet as well atm)! I'm definitely keen to hear what happens tomorrow, but maybe putting your post in spoiler tags to help protect your account could be a good idea!
I feel like the probability of that happening so many times in a row would be quite low, but a bug seems unlikely because when was the last time the lab ray was updated or changed in any way? I have read that pets with lower levels are more likely to be reverted back to level one, but I feel like that's not too applicable here either...is your pet a reasonably low/high level?