Balls desyncing
The server fails to update the new positions of balls resulting in the client shooting at ghost balls and inadvertently or unintentionally scratching. This can also result in premature game loss if the 8-ball becomes affected.
Balls teleporting
Sometimes the server is slow or inconsistent to update the new positions of balls, with the balls appearing to pop in to their new positions. This seems to happen a lot when striking the 5 five balls that remain packed behind the 8-ball
Iffy collision
Sometimes the target ball will appear to completely sidestep/strafe the cue ball, with the cue ball phasing right through. This is probably related to desync though, with the target ball’s actual physical position being just shy of its visible position.
It’s also worth mentioning that sometimes, at the beginning of a new shot, billiard balls will move autonomously without player interaction.