The Bug
The "Gear equips" sound plays when equipping or removing a saddle from a horse wearing horse armor.
Reproduce
Get a horse
Tame it
Equip horse armor on it
Equip a saddle on the horse
Observed Result
Both the "Saddle equips" and "Gear equips" sound play when placing and when removing the "Gear equips" sound plays.
Expected Result
Only the "Saddle equips" sound would play when equipping and no sound would play when removing
I can also confirm this behavior.
It's important to note that this issue also occurs with horse armor alone. In other words, simply equipping or removing armor from a horse plays the "Gear equips" sound.EDIT: That issue is MC-251921.