Sounds like a plan to narrow down what happened 
@deadwood
I copied your Icon Library sources from ABIv11 to my x86_64 build system then recompiled it.
On the IcarosDesktop x86_64 with system files from about two years ago, mid 2019 the icons display just fine.
For the sake of the pseudo-scientific method I will repeat the process to verify the results.
So it's entirely possible that the latest ROM file you posted could work correctly on AROS One 68k from February 2021 like he said.
Apologies to AMIGASYSTEM. I didn't mean to doubt you good sir.

@deadwood
I did the easy part. I'll leave it to the master to do the hard part.
It must be graphics changes outside Icon Library at fault.

If it's not a graphics driver change could it be a change in Wanderer? How would we test Wanderer changes?
Ronny Beck was making changes to update Workbook for Apollo OS. Maybe workbook is sufficiently advanced to show icons on AROS 68k? If it works it could be a problem with Wanderer.
Just a few ideas.
