Could it also be the TV?

Is the error reproducible? In other words, does the distortion always occur at the same point in the film? If not, check the cable and play other 4k sources on the TV/beamer. If reproducible, the player reader seems to have real problems.
If the error only occurs once per film, always at the same point, it could also be due to the BluRay, since as far as I know these are written several times (one above the other). If you then switch from one layer to the other when reading, this can lead to brief faults.