https://bugs.winehq.org/show_bug.cgi?id=47813
--- Comment #4 from theristhewolf@gmail.com --- Sorry for the slow response; I've been busy the past few days.
I can confirm that using winetricks as described earlier in the discussion fixes the issue I was facing in trying to reproduce the described bug in a vanilla version of wine. I can also confirm that the bug desçribed in the opening post is not present in winehq-devel 4.17; games now successfully launch from the Itch client without producing a warning or an error.
Thanks for the patch and the prompt fix.