I see a similar but slightly different behavior since aprox. 2 weeks (so NOT related to todays update but might be connected to your issue):
I have a Kettler trainer which is connected via a mobile app (Bluetooth -> ANT+)
When I start a training I get in ERG mode 25 watts (the minimum) during warmup. The next changes in Wattage are 100% correctly sent and handled and handled by the trainer. For the Warmdown I also get sometimes no change in Wattage (Trainer sticks to the last transferred watts).
This is most probably no direct problem of VirtuGO … BUT other applications behave more clever as they seem to send the wattage in ERG mode more often than only once when a change in Wattage is happening.
In Zwift I sometimes see a message “ERG connection lost, reestablishing ERG mode”
An improvement for all users with not 100% stable trainers/connections would be
a) to send the wattage more than once
b) ability to reconnect without leaving the training