Yeah it happens on my cousins also he never had issues on stormblood but he got shadowbringers and like once in a while the game will lock up.

Example.

He'll swing his weapon but it doesn't move he'll slide everyone else is moving his skills are in movement and he can still attack but everything is locked up.
then after probably 20 seconds the moves catch up and it goes back to normal.
this is on a windows 10 pc 64 bit

he already changed downloaded a new graphics driver but problem still exist.

he once entered crystarium and moved to north end and locked up pictures on the icons were missing and the game looked like it was trying to catch up with itself.