Not seeing anything at all that would change the properties in the recipe.
Can you check that your diy_BAC_Armour_group_one.txt has the recipe like below?
Alternate guess is that maybe its a too many items in your homestead area bug which has done quirky things, usually a deletion, in the past.
>>>>
//Spectacle helm
.Iron spectacle helm. *CARPENTRY* %-60% /8h/ [effort:3] [phys:hands, arms] |2|
{Steel dome} [remove] [ground] '+initial frame'
{*steel billet} #2# [remove] '+add curved plates'
{Iron nails} #0.25# [remove] '+as rivets'
{Leather} #0.25# [remove] '+as suspension and head band'
{Ball iron hammer} '+hammer complex shapes'
{Pliers} '+hold while hammering at odd angles'
{*anvil*} [ground] '+to hammer on'
{Medieval drill} [ground] '+to drill rivet holes'
[PRICE:30.6]
// reference showed price 520 torches = 30.6 squirrel hide