What happened?

The Nether Ruby armor lights its user on fire when the user takes damage from a distinct entity source.

Expected behavior is to not be lit on fire, or to not take damage from said fire.

BetterNether

7.1.2

BCLib

2.1.3

Fabric API

0.66.0

Fabric Loader

0.14.10

Minecraft

1.19.2

Relevant log output

No response

Other Mods

No response

Update - after further (unintended) testing, it seems to only affect zombies or other hostile/neutral enemies that attack you with melee. I assume its setting you on fire due to the main game feature of a zombie on fire transferring the on-fire state to the player.

Yeah, you probably catch fire from the attacker. That would not be a bug, but simply a disadvantage of the enchantment.