Welcome to our forum.
That's a circ pump tub right? Sounds like you have a flow problem? Is the filter good? Circ pump good, how old? Are you saying that you get the flow error because the circ pump stops working, causing the tub to use winter logic to turn on the jet pump?
A solid FLO error means that the sensor is seeing flow when the circulation pump is supposed to be off. If you have a solid FLO and the circulation pump is not running, then the flow switch is either stuck closed or faulty.
Is the circulation pump running constantly with the FLO error or is the main jets pump