Villagers still hold a trade offer in their hand if the player is in spectator mode

The bug

When a player switches into spectator mode while standing in front of a villager and holding an item that this villager wants to trade, the villager will keep the item equipped for a while.

To reproduce

1. Stand in front of a villager that has available trades
2. Hold an item that the villager wants to trade (for example, emeralds)
3. Switch into spectator mode
   → The villager is still holding the item it wants to trade

Video

Minecraft 1.15 Pre-release 6 2019-12-07 15-52-55.mp4