Not necessarily bugs, but some animations in the game have slight issues.
The most obvious to me is the return stance #5 (the Federer one, created by Neeky McDeez).
When moving back and forth, the left hand goes through the thigh. The right hand looks odd, and the racket goes through it when spinning.
When the left arm is at its most stretched point, it almost looks like the elbow is overstretched. Not necessarily wrong, but it looks a little odd.
There's a vid of the entire animation here.
Similarly, the applauding gesture where you're clapping with your racket has the same "elbow overstretching" issue which looks very odd.
This one could be attributed to me playing from a junior career, though, as I've noticed that the elbow overstretching isn't as pronounced when my player is a year older and 1m60 than it was at the start when he was 1m48. The racket being too big for the player requiring the arm to go "too far"???
Animation here.