Hi, I have similar issue with version 4.3.
All my channels are mapped normally with no issues by using the version 4.2 in libreelec. However, when using 4.3 (pi lite headless) I have issues with ignoring channels. Specifically, a single mux with 10 channels can't be mapped for some unknown reason. I Know it works because my other servers running 4.2 working fine. I've tried several options found online but nothing has worked for me so far. Lastly, I manually mapped a channel and initially seemed to be a solution, but when I try to play the channel, it says "no free adapter available" which is not true.
I'm wondering if I can install the 4.2 version but I don't see any previous versions available, just the command to install tvheadend which is the latest version.
Any help would be much appreciated, thanks.