Mobs spawned by trial spawners will not drop gear that they picked up from dead players.

When a player dies to mobs in a trial chamber, gear such as their armor, weapons, and shield may be picked up by these mobs. When these mobs are killed, they do not drop this gear on death. In all other scenarios, mobs would be expected to drop this gear. This can be especially impactful when players have invested a lot of time into creating this gear.
Steps to replicate:

• Go to trial chambers
• Equip gear
• Die to mobs spawned by a trial spawner
• Kill mobs that have picked up your gear
• Gear does not drop