Wandering trader in the nether crashes the game

A wandering trader walked into my nether portal, once I went into the nether the game crashed. I restarted the world and it happened again. I went into another world, prepared the "/kill @e[type=WanderingTrader]" and joined the nether again, instatntly executed this command and the game didn't crash. 

Unfortunately I didn't screenshot the error. But it was a NullPointerException.