Missing symbolic icons inside some GTK4 apps

[grungefox]

Problem:

While using Bottles and Gradience, I found out that some symbolic icons are missing inside these apps and instead shows the same weirdly pixelated error icon. And only few of them are actually missing, which is even more odd to me.

Examples:

Gradience welcome screen with missing Update icon

Bottles Library tab with missing Heart icons

However, this issue isn't present when switching to original "Adwaita" icon theme:

Switching to "hicolor" via GNOME Tweaks created the same results as my icon theme did, which may suggest that there is something important going on with "Adwaita".

Tried solutions:

At first, I tried editing index.theme (which I originally copied and tweaked from original "Adwaita") and deleting all links to obsolete directories that may interfere with Adwaita folder (or just simply leaving only links to /scalable/apps/ and symbolic/apps/), but this didn't help.

I also tried copying symbolic icons (particularly heart emoji which is duplicated as both emote-love-symbolic.svg and emblem-favorite-symbolic.svg in "Adwaita" folder), even though it's against rules of this project. To my surprise, this didn't work either, and I ran out of better ideas.

Conclusion

This issue may be due to devs of those apps forcing use of icons from "Adwaita" and ONLY this, or I'm just missing something.

If anyone knows a solution for this, please leave a comment down below, thanks. I will still keep working on this project besides of this problem, no matter how annoying this is to me.