Yes it is worse.
English is not my native language, but I will try my best ..I get this issue with or without the fade in setting, please file a bug via the app!
Do you have a sub connected to the wiim amp? In my case when I connected the sub to the sub output via rca cable (streaming from Tidal), the clicking and popping were present ("fade in / fade out was on") , but only through the sub, through the speakers, there was no problem. I solved this by connecting my sub in parallel with the speakers (my sub B&W ASW 608 has also speaker-level inputs). I don't use sub functionality of the amp, so the sub is set to off.