ERG mode disabled in middle of workout

Using a Wahoo Snap with Mac OS 10.15.3 with Bluetooth. I’ve been doing workouts on Zwift for months without any real issues but for the past couple of days (since updating OS possibly) while in the middle of a workout ERG mode will suddenly disable. It happens in the middle of block without any change in wattage, just out of nowhere. ERG mode won’t restart.