I’ve been experiencing an issue this winter (where I did not have the same problem with the same hardware last year):
I am using Apple TV (Zwift app), iPhone XS Max (Companion app), Whaoo Kickr, Tickr, Cadence. All bluetooth, all latest version.
During a ride all bluetooth data stops. The companion app, and Zwift, shows blank values (not zero, but more “-” missing). This drop out can last for under a second, but can be up to over a minute.
Very frustrating when on a group ride and you have to try to chase back on!