I'm going to TL;DR this:
Symptom:
-Live TV on Leelbox Master, the program info on the bottom would flicker and not go away.
-Live TV on Leelbox MQX Pro, same thing.
-Live TV on NVIDIA Shield, same thing.
-Live TV on computers are fine. Live TV via HDHomeRun app on Leelbox is fine.
Observation:
-Log was getting spammed hard: 1-2 KiB/s. The spamming stopped when stopping Live TV.
-Only occurs in Live TV. Watching recording is fine.
-Leelbox is running old version of Emby. Shield is running latest.
-Swapped the two (because one is wired and one is wireless) and all three devices did the same thing.
Attached logs.
logs.zip