Wandering trader drinks potions of invisibility at night even when difficulty is set to peaceful

I set my game difficulty to peaceful, spawned wandering traders, and they still drink potions of invisibility. Maybe the wandering traders thought there are monsters outside trying to attack them. Someone please fix this!

 

 

How to Get this bug:

Step 1: Set difficulty to peaceful

Step 2: Set time to night

Step 3: Spawn wandering traders

 They still drink potions of invisibility