Two questions for you and jis.
1) What firmware version are you currently running?
2) Are we talking about this Tasker app from the Play Store? https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm
And noted on the other issues you raised.
This problem is affecting all Asus proprietary system apps like File manager, Clock, etc.
_jis_I've been talking with him via PM. I did screen recording showing how to set up a simple theme toggle via Tasker and also recorded logs while doing so so they could follow along.
I have this problem in all firmware versions from 110 till 137.
I didn't tested in 63, 68, 73, but it is probably issue in Asus A10 from the beginning.