[MC-139528] Pillagers and piglins can move their arms into their heads

The bug

When a pillager tries to aim at the player, sometimes the arm moves into its head.

Linked issues

is duplicated by 4

MC-224361 Pillagers yet again have glitched out arms Resolved

MC-164274 Pillager has a strange arm Resolved

MC-162795 Pillagers' arms will face the wrong direction when you move Resolved

MC-300084 pillager's animation misalignment when hold the crossbow Resolved

relates to 1

MC-83137 Skeleton's arm goes into body when shooting arrows Reopened

Attachments

Comments 18

DrownedZombie 2020-02-15T00:50:38Z

Updated title to have piglins.

Orbic 2020-02-28T00:23:38Z

Still in 20w09a

Orbic 2020-03-04T22:21:10Z

Confirmed for 20w10a

Orbic 2020-03-11T21:20:09Z

In 20w11a

Orbic 2020-03-18T21:31:44Z

In 20w12a

8 more comments

Avoma 2021-12-08T17:19:54Z

Can confirm in 1.18.

Avoma 2022-01-02T18:10:44Z

Can confirm in 1.18.1.

Avoma 2022-04-03T19:34:16Z

Can confirm in 1.18.2 and 22w13a.

[media]

Avoma 2022-08-19T15:50:14Z

Can confirm in 1.19.2.

Ampflower 2024-06-29T08:47:42Z

Can confirm on 1.21 for players in boats, piglins with crossbows in boats, and pillagers generally.
Other mobs seem unaffected when forcefully given a loaded crossbow.

Digging around in 1.19.2 with official mappings (yes, I know, it's stale but I don't expect much will have changed),

IllagerModel, HumanoidModel and PiglinModel, all models capable of rendering a loaded crossbow for illagers and common bipeds (excluding villagers), delegate to AnimationUtil.animateCrossbowHold, which does all the rotation calculation on the arms and head. It might be viable to use Mth.clamp to as a means to limit the rotation, if messing with the math to limit it otherwise isn't feasible.