Thankssometimes these tricks may help video stuttering
1. disable all CEC from player and TV
2. change your colour space in the Blu ray player to 4:2:2 (from Bob Pariseau at avs)
this decreases the bandwidth of the signal travelling from your player , with preserved original fidelity of the data encoded on the disc
3. disable wi fi from you player
4. all the usual stuff like make sure no dust or finger prints on your disc , make sure your HDMI cable is Premiumcertified , make sure your player firmware is up to date , make sure all HDMI terminations are snug in their sockets and make sure your discs aren’t pressed in Tijuana Mexico (joke )
on my Panasonic 9000 once I changed the colour space settings the player dramatically had less freezing on UHD discs over last 3 months