Of course the Gripper! Looked like it was mounted higher than the payload chasis - did you source the additional bouyancy from blue robotics?
Definitely found different laptops can work differently so maybe the ‘lost control’ issue is not directly related to the BlueOS/BlueROV as mine has been working stable since I’ve changed. Not sure if its entirely relevant but see this thread for techniques/issues to diagnose communication issues that might be helpful before you get a new laptop!
One thing I have noticed is when my bluetooth xbox controller goes into sleep mode I get the lost connection error message. Think there is a setting somewhere that you can set an action according to the number of seconds where there is no user input. Although thats not enabled on my setup it might be worth checking the controller connection is stable as well.
Have an interesting field test today after doing some tuning of my setup and will let you know when I upload some video as might be of interest.