Thank you for your response.
That sounds like some good advise, but I think I still have something to learn about icon packs and/or themes. Like are icon packs complete replacements or more like overrides? If an icon pack doesn’t contain an icon for an app, will no icon show, or will the original icon of the app load?
I added a screenshot to my original post (now that my account has been upgraded to “Basic”)… and so what I’m still wondering is… was the issue always there? or did it only start happening after I applied a new global theme (which swapped to a new icon pack)?
What makes me wonder if the issue was already there is that shortly after I posted this thread, I used PAMAC to install GIMP and it’s icon worked right away… whereas Discord (also installed by PAMAC) had issues with its icon.
Even stranger is that I’m somewhat confident Manjaro Hello’s application list was “complete” when I first launched it… now its missing some icons too; shown as red nots.