While 80% humidity isn't bad for a BP, it is higher than it needs to be. 60% normally is more than sufficient. Only during shed do you need to boost it closer to 80%.

This time of year a lot of BP's will go off food. I would just keep offering once per week. If a few more weeks go by it might be time to try some more drastic steps, but for now I would just try to wait her out.