I would recommend it even less. Especially if you train MMA striking. I know some people really enjoy grappling after medicating but that is a bit different. I personally never train high, did it once and hated it.
The problem with MMA and being toasted or something is that there is so much going on it's easy to lose concentration. Furthermore, many friends of mine and myself have found that we blink a lot more too, which is BAD if someone with firing punches at your head. My friend and I were sparring once after a vape session and we both blinked everytime a punch came at our way. We both don't usually do that, so it was a pretty weird experience.
I just feel like in a sport like MMA where you are focusing on so many different things (striking, grappling wrestling, transitions from striking to grappling or grappling to striking, submissions, etc) doing it baked probably isn't a good idea, at least for live drilling.
Now, as far as thinking and planning new strategies or techniques or simply just individual training (like hitting a heavy bag or a speed bag), there shouldn't be a problem. I'll find myself shadow boxing for an hour straight sometimes, don't even realize it