The character app has several bugs that apply bonuses it should not.  A barbarian wearing armor should not also receive the unarmored bonus.  A Paladin receiving a shield of faith bonus when the spell is not cast, and further is not even prepared.  A wizard receiving a bonus for mage armor at all times, even when not cast.  And then there's the attunable items that require other items, except they don't on the character app.

If you'd like, I've created a python script which corrects most of these errors.

Why does it always seem (character app, encounter builder, etc.) that someone builds something that functions, and never goes back and fixes the issues.  They just move on to the next thing and forget the past, ignore the issues, etc.

Quote from Obsession469>>

The character app has several bugs that apply bonuses it should not.  A barbarian wearing armor should not also receive the unarmored bonus.

  A Paladin receiving a shield of faith bonus when the spell is not cast, and further is not even prepared.  A wizard receiving a bonus for mage armor at all times, even when not cast. 

And then there's the attunable items that require other items, except they don't on the character app.

 I'm unaware of any attunable items that have other item prerequisites. (Also, enforcing something like that would be complicated.)

Probably referring to Hammer of Thunderbolts, but it doesn't require the Gauntlets and Belt to be attuned, just to access a couple of the Hammer's features. So that one's up to the player to keep straight.

Go attune to a hammer of thunderbolts, and none of this is homebrew.  Next, go be a barbarian with unarmored defense and put on armor.  Shield of faith is a paladin spell, and the bonus is automatically applied.  So my paladin that doesn't even have it prepared has the ac bonus.  I have verified this.

Again, I have a script that applies these items properly. including the hammer rules.  I use my own tracker for hp/ac.

As written:  Giant's Bane (Requires Attunement). You must be wearing a belt of giant strength (any variety) and gauntlets of ogre power to attune to this weapon.

I don't know what you mean by "not supported"  these are both things in DnD, and they both apply a bonus just for having it in the known spell list.

Click on AC and start looking at the bonuses applied.

Quote from Obsession469 >>

I don't know what you mean by "not supported"  these are both things in DnD, and they both apply a bonus just for having it in the known spell list.

Click on AC and start looking at the bonuses applied.

D&D Beyond does not do this for either Shield of Faith or Mage Armor. I'm looking at multiple characters that know these spells and it's not happening.

You've likely either got an override in there or some sort of third-party extension affecting it.

Quote from Obsession469>>

Again, I have a script that applies these items properly. including the hammer rules.  I use my own tracker for hp/ac.

As written:  Giant's Bane (Requires Attunement). You must be wearing a belt of giant strength (any variety) and gauntlets of ogre power to attune to this weapon.

I don't know what you mean by "not supported"  these are both things in DnD, and they both apply a bonus just for having it in the known spell list.

Click on AC and start looking at the bonuses applied.

 Since they don''t, I suggest your script is the problem.