Game Flavor (please complete the following information):

• Flavor: Retail

Describe the bug
I could be wrong here, but I feel like the Appearances toggle under the General settings isn't really "Account-Wide by default" like the tooltip and checkboxes indicate:

I mostly play a paladin, so most of the appearances I have collected are ones I can use as a paladin. If I keep my ATT settings as they are in the screenshot above (Paladin Unique Mode, with Appearances checked, and the Account-Wide Appearances checked by default), then my Appearance tooltips appear to be paladin-specific. For example, the Residual Memories tooltip says I need a total of 41,000:

but I know that's not true, because if I switch ATT to Account Unique Mode, I see all the non-paladin gear I haven't yet acquired, and I need 146k for it:

This is not unique to the Residual Memories currency either, it was happening in Remix with Bronze, and it happens with just... regular reputation caches, e.g. (Scuffed Krokul Cache, AU vs. U mode):

To Reproduce
Description should explain the issue sufficiently.

Expected behavior
Class/Character Unique Mode (U) should respect the Account-Wide Appearances checkmark, like it does for other Account-Wide Things, like Mounts or Pets.

Screenshots
Included in the description.

Additional context
N/A

It's just a small misunderstanding of what Account-Wide (now Warband-Wide) and Account Mode mean in regards to how ATT treats the data.
Account Mode means that you want to Filter the visible Things assuming that any character on your Account can be utilized to collect the Things. Thus we do not filter by Armor types, classes, races, etc. and hence why so much more is visible to collect in Account Mode

Account-Wide on the other hand does not alter the filtering of Things in ATT, but rather only grants credit to collection of Things based on whether another character has already collected it. So essentially for per-character collectibles, this setting means you only need to collect it on one character so that any character sees that Thing as collected.

The reason some of those Things (Appearances, Mounts, Toys, etc.) are automatically Account-Wide is because the collection of those Things are NOT based on being per character. If you unlock an Appearance on one character, it's unlocked for any character on the Account by Blizzard, so ATT has no reason to distinguish that via a checkbox.

So yes everything looks to be working as intended. Character Unique shows Appearances that Character can use but has not been collected, whereas Account Unique shows Appearances that ANY Character can use but has not been collected.