Two other rational, though more sinister/unfortunate conclusions could also be that you smoked some bad (ie fake or laced) weed and someone spiked your drink at the bar.
Situation 1: did you have and smoke more from that same batch any other times? /Did your friend bring their own stuff?
Situation 2: could have gotten drugged unfortunately, but fortunately left before blacking out and managed to get yourself home.
100% the simplest and most harmless explanations are most likely, not suggesting that the worst case scenario is probable. Just thinking of other possibilities.
My only experiences with missing time are most likely epilepsy-related, so I’ve never thought much of one beyond that. Seizures can feel pretty strange by definition, so I don’t think I would know how to guess if something else caused a given episode.
As a smoker and one-time bar-goer, I’d agree those sound unlikely given the details. Shared lost time in that first situation is definitely an interesting one, strange world! I’m sure it was hazy, but did you both start the lost time (and/or come to) at the exact same moments?