Hi Vincent,
I’ve had the resistance issues via Bluetooth on two trainers I have used. Happened on the previous IOS version and the most recent update, v1.0.30327. It appears at random and I cannot pin point what may be causing the issue. When it drops the resistance the units are all paired correctly in the pairing screen.
I am also using a Wahoo Blue SC sensor and Bluetooth heart rate monitor.
At times I am running my iPhone with music playing through a Bluetooth headset however all associated apps are off, except for Zwift Companion (which I have switched off mobile link). Im not sure if the drop outs in resistance are related to it trying to send the signal to the iPhone instead, even though all apps are closed and only Bluetooth headphones are connected.
Trainer - Tacx Vortex (latest firmware)
Device running Zwift - IOS
Connection - BLE
Zwift Game version - v1.3.30327
Firmware - latest from Tacx
Mode - sim
Trainer - Wahoo Kickr Snap v2 ~2017
Device running Zwift - IOS
Connection - BLE
Zwift Game version - v1.3.30327
Firmware - 2.3.62
Mode - sim