Set custom telegram theme in alien dalvik

I use telegram on AD once in a blue moon to make calls, otherwise Fernschreiber is excellent. I can see my custom theme in the list but it isn’t applied. Does anyone know why this is? I spent a long time making this theme…there are many hundreds of page elements that can be changed - and I changed a lot. It imports fine to telegram desktop.
BTW this is the Tg from aurora, I tried TgFoss from Fdroid but calling didn’t work.