Just to put in some context. Holloway is reported to weight around 180lbs about a week before fight-night. Meaning he's doing a 180-145 weight cut. That's 35lbs, which is 19.5% cut. A weight drop of 8-9% due to dehydration is considered "severe" and is correlated with such wonderful 'side-effects' as cyanosis, delayed capillary refill, hypotension, and coma.
I would assume it's ENTIRELY plausible that a weight cut if nearly 1/5th of your own body weight could cause, if only indirectly, having a stroke.
The fix to shit like this is simple, make it so weight-ins can be no more than 6 hours prior to the start of the fight. No time to re-hydrate = no severe weight cutting.