Thanks for the reply.
Starting a new airframe or just use the not-FPB mode and it all works like it should. So, not a hardware issue.
I, somehow, got things into a state where it acts as detailed above. I had been reviewing my joystick settings, but not changing anything. Maybe that has something to do with it: entering joystick setting...moving axis around...exiting settings and throttle no longer can be moved.
If it happens again, I'll return with some more information.