The snapshot notes suggest that all UUIDs stored in NBT should be converted to the new int array format. Villager gossips still use the old two-longs format.

Steps to reproduce:

• Summon a villager.

  /summon minecraft:villager

• Hit the villager, to generate a gossip regarding yourself.
• Check the villager's NBT. 

  /data get entity @e[type=minecraft:villager,sort=nearest,limit=1] Gossips