Sound and video “stuttering” on sports networks

This has been happening for the past few weeks now. It’s primarily happened on sports networks/sports package channels (NHL network, MLB network, MASN) where both the sound and picture are pixelated and stilted. All lines were secured and we even got and installed a new splitter. We got a new cable box and that initially seemed to make a difference but now it’s the same if not worse on the above mentioned channels. It’s basically unwatchable which is insane for how much we pay for cable. Any idea how to remedy this?