This happened immediately after opening a saved lister layout using a button to execute Prefs LAYOUT="Opus Config". I had one other layout open at the time. Both layouts are used on a daily basis and I have never seen this crash before. Opus (10.1.0.0.4569.x64) successfully closed and reopened the two listers.
If it's not repeatable and has only happened once so far then we don't have much to investigate.
The async-icon-thread requests icons for the files being displayed from the Windows shell, and in turn shell extensions that may provide icons for certain types. So the crash might be due to a shell extension, rather than Opus itself.