Looking forward to a reply as well. Have the same problem. Since each individual TV is doing its own scan, it is likely something inherent in the manufacturer's software.
As an aside I just purchased a used 2015 Salem Hemisphere. When we were at our first campground they had cable, though the connection wasn't very good. Anyway, usually when you use your TV with cable you shut the booster off. I initially did that but when I scanned for channels I got maybe three back. Just for grins, I then turned the booster on, re-scanned and it came back with 20-something channels.
2015 Salem Hemisphere
2013 Ford F150; Eco Boost; Super Crew,
Max Tow Pkg