Sorry to hear your woes BullyDogMom, but if it's any consolation a lot of my Phals are behaving exactly like yours! Mine stay indoors all year, in the same spots, so don't even have a twice yearly change of environment like yours.
But!
I think the guys on here have solved my mystery, if not yours!
I switched our gas fire on 2 weeks ago for the first time this winter and it has been on every evening since. Because of the strong winds we've been having I have only had one small window open, not creating a through draft/good ventilation. All the phals in connecting rooms have been affected and only the ones in a completely different part of the house haven't suffered.
I hope you manage to resolve your issue!