PF seems to either refuse to adjust or is overdoing it. I've rarely seen a sensible inbetween that is helpful instead of leading to more chaos or pointless discussions.
Either people stubbornly stay on their spot or they move over if someone isn't instantly or 30s ahead of the mechanic happening at their assigned spot. I've seen it a lot when PFing during 2nd ShB tier, especially on Ramuh spears. If H2 wasn't at their Narnia spear the moment Ramuh jumped, H1 would sometimes go to their spear. Or the tank would instantly move to the 3rd spear if they didn't play M1- M2 - tank order if the melee wasn't moving right away.
"you're h2"
"i know"
"then why weren't you standing on your spear"
"because you already took it"
"yeah because you DIDN'T"
Seen it go like that several times.
C'mon, they don't have to move out of melee range at the start of a 10s pointblank cast or move to your Thunderstorm corner 20s ahead of it happening. If anything, it just increases the chance of missing buffs and heals and often lead to deaths on E11s during Cycles because they outranged the heals on the only heal check the boss had.
It's good to keep an eye on things and adjusting if they notice someone is sleeping on mechanics but running to a different spot just because someone didn't beam there and then going all "you were at the wrong spot!" isn't helping. I generally wait for as long as I can safely make it to the different spot to give them enough time to move with slidecasting etc.