I think the issue comes from the Handwraps pulling the size information from Unarmed strike and then having the size category for the damage dice increased by a size category.
By default, Handwraps has Post-attribute priority 10000, and Stonefist Gloves has Pre-level priority 10000.
Stonefist Gloves has the same priority and timing as the Impact enchantment.
The recommendation to check out the Impact enchantment also let me to find a bug with it when it interacts with Handwraps. If you add Impact to Handwraps, the size damage dice for the weapon doesn't increase even though it should (Med to Large).
In addition, both Unarmed strikes and Handwraps are weapons labelled as "Size doesn't matter" meaning that the damage dice for the weapon changes with the player's size.
One way to fix it might be to disable the "Size doesn't matter" option, but I don't know what that'll effect in the long run.
Original code for Handwraps below
Code:
--------
Handwrap
Post-attributes 10000
perform hero.child[wUnarmed].pulltags[wMain.?]
perform hero.child[wUnarmed].pulltags[wCritMin.?]
perform hero.child[wUnarmed].pulltags[wCritMult.?]
perform hero.child[wUnarmed].pulltags[wType.?]
if (container.ishero = 0) then
perform container.parent.pushtags[wMain.?]
perform container.parent.pushtags[wCritMin.?]
perform container.parent.pushtags[wCritMult.?]
perform container.parent.pushtags[wType.?]
container.parent.field[wDamage].value += herofield[tSize].value
if (tagis[Helper.DamageDown] <> 0) then
perform container.parent.pushtags[Helper.DamageDown]
elseif (tagis[Helper.DamageUp] <> 0) then
perform container.parent.pushtags[Helper.DamageUp]
endif
else
field[wDamage].value += herofield[tSize].value
endif
--------