DEVICE: Samsung Galaxy tab A

In the most recent build of the 0.16.0 update (0.15.9.2), I have noticed that guardians (and Elder Guardians) will continue to sink while they are firing their beam. They are supposed to remain stationary while attacking even if in the open water. Because they sink while attacking, they often lose their target while attacking before any damage can be inflicted. I watched as a squid was repeatedly locked on to by a guardian that was below it but the Guardian would sink out of range then swim back up to attack again then sink out of range again. This would continue for a while. It would also happen when I was above a guardian and it tried to attack me (unsuccesfully). Because of this, guardians can only sustain a damaging attack while they are resting on the ocean floor or on the side of the monument. This bug makes guardians ridiculously easy to escape now. Thanks for reading and hopefully fixing!

STEPS TO REPRODUCE:
1. Enter a new world in creative
2. Place a guardian and a squid together in a body of water. (Make sure the Guardian is not resting on a block)
3. Watch as the Guardian sinks down while it is locked on to the squid. It is supposed to remain still (without sinking) while it is locked on to a target.

EDIT: Just added a video of the bug!