Yes, the armor appears as the default flesh color in the collection icons. That I am aware, this is unavoidable. Vanilla armor, and most if not all cosmetics, are rendered as this default color and then are dyed to their familiar color on generation as if they had been dyed. Since the collection UI cannot call for dye colors, this cannot be changed and we're stuck with the icon colors seen.

If I am wrong, however, I will adjust the entries in an update.

After an idea from Seyjin that mushed me to look for an easier (read as "lazy") method, fumbling through Aseprite 0.9, and hamfisting through code, I can begin colorizing the icons without having to create "dummy" items to replace the icons. Turns out that the collections support absolute calls to icons (now if only I can get this to work for items and objects as I've been told it's supposed to). For example:

What does this mean?
It means that I can take the icons.png that exists for each armor set, replace the default palette using color values found in the armor files to create the colorized icons, then split it into individual head/chest/legs icons. This will be a slightly drawn out process, as this means I'll manually palette swapping 81 sprite sheets, splitting them into 242 separate files, and coding them into the collections. While I hope to have the process done within a week, a safe estimate would be a month (allowing for life, job, patience, attention span, Castlevania on Netflix, etc.)

I will be rolling out micro-updates as I finish them. They will update items that have already been unlocked seamlessly, so you may suddenly see icons colorize from one load to another.