New Aircraft new Liveries.
Just like any other aircraft in the sim a separate aircraft needs it’s own liveries. Since the FlyByWire A320 is now an aircraft on its own it needs new liveries. The A320 liveries you have already still work, but only on the MSFS A320 not the FlyByWire one.
So the livery creators need to convert the old ones or make new versions.
I read somewhere that FlyByWire is working on a converter but I wouldn’t rely on that.