I would remove the "booster" wall plate and examine the coax connections.
It sounds like a coax fitting may be bad on either the plate itself or the splitter it then connects to; or both.
It is also possible the plate itself is bad.
Lou, Laura, & Freya the wonder dog
2008 GMC Sierra 3000HD Crewcab SB Allison Duramax
2019 Flagstaff 8529FLS - Pullrite 3300
HAM CALLSIGN - KC3FFW