Maybe Not a Bug? Parry AC Bonus does not stack with AC Shield Modifier

[Barley]

Where:
Mist Camp

When:
Tested today on two characters

What:
I've tested 2 Monster Hunter magic items: the Dented Holy Symbol with Tirgar (a Monster Hunter), and I tested Sturdy Torch with Barley (using UMD).
For both situations, the Tumble AC does not stack with the item's AC Shield Modifier.
(Neither do the Shield Modifier items halve the Parry AC, without Shield Parry, which makes sense that they do not halve it).

So, is this because Parry AC is the same as Shield AC when not holding a shield? If so, this is not a bug.
However, it's a bummer!
If this is the case, it would be helpful for the items to be something other than what is carried in the shield hand (holy symbol and torch). Such as a ring.

[zDark Shadowz]

Assuming there's a mistype tumble > parry due to subject & title.

Yup, when you aren't holding a shield, the Parry bonus is considered Shield AC, and when you are holding a shield, the parry bonus becomes Dodge AC.

This is likely done this way so that people who don't use shields won't hit the +20 AC dodge cap as quickly.

If you have offhand torch items that are giving a Shield bonus to AC that aren't actually shields, that is going to cause some weirdness, but it's probably an extremely quick fix. Thanks for making the report and specifying item names along with their item types, should make it easy for devs to fix.

[Barley]

Yes, I mistyped Tumble, but should have typed Parry. I've fixed that now!

[Barley]

So, does this mean that the Two Weapon Defense feat that grants +1 Shield Bonus when wielding two weapons also does not stack with the armor bonus of Parry?

[Favee]

So, does this mean that the Two Weapon Defense feat that grants +1 Shield Bonus when wielding two weapons also does not stack with the armor bonus of Parry?

Two weapon defense and bonettis defense feat trees do stack with parry AC.

[Madame Trousers Son]

There's probably a couple of reasons why Shield Parry grants Dodge AC instead of Shield AC.

 (1) The script would be more complicated. Multiple Shield AC bonuses don't stack, so you'd have to calculate what the total Parry AC bonus should be, then add the difference to the Shield's base AC. e.g. if you had a +2 small shield, and you should be getting +3 Parry AC, then the script would have to calculate that it needs to give you a total of +5 Shield AC. Moreover this calculation has to be done separately for bludgeoning AC, slashing AC, and piercing AC, since some shields differentiate on this.

(2) It would arguably be too strong. It's one Feat giving potentially multiple points of AC. At least Dodge AC has a weakness, since you can lose it in some circumstances.

Two Weapon Defence and Bonetti's simply add a flat modifier to the base Parry AC calculation, and moreover stick to the guideline of one Feat = +1 AC.