Bug description
I've seen this happen in the Fabric 1.18.1 version of the mod. Not sure about other versions.
Tested only in Singleplayer. (I'm a loner.)

If you use an identity that's not supposed to be attacked on first sight by the Piglins (a hostile mob identity) but you don't wear any gold armor on yourself, the Piglins will start switching back-and-forth between their raised-sword and neutral animations and spamming their anger sounds.
This does not have any effect on their behavior, though, and they will remain neutral until they find another excuse to attack.

This seems to act like a client-side prediction issue, I've seen similar client-side prediction mess-ups on other games.

Game log:
Should I really upload a log?

that happened to me as well, i just morphed back to a player with gold armor

Same issue on 1.18.2 on multiplayer.
I muted them with https://www.curseforge.com/minecraft/mc-mods/omega-mute-fabric
Then used these commands in-game:
/omegamute mute entity.piglin.ambient
/omegamute mute entity.piglin.angry
They still rapidly twitch their weapons up and down but at least it's not making such a loud noise anymore.

same issue i hope it gets fixed in the next update