Note the lack of an armour equipping subtitle in the screenshot provided.
MC-166296
Mobs picking up and equipping items does not play the equipping sound
Resolved
Fixed
4
muzikbike
mgatland
Confirmed
Normal
Sound
missing-sound
1.14.4, 1.15 Pre-release 1, 1.15 Pre-Release 2, 1.15 Pre-release 3, 1.15 Pre-release 4, ..., 20w08a, 20w09a, 20w10a, 20w11a, 20w12a
20w18a
Retrieved
I can't hear any equip sounds going as far back as 1.12. There is a popping sound when the mob picks up the item (that sound can also be heard in 1.15 Pre-release 2), but no equiping sound.