Villager Trades Not Offering New Trades

Upon using the new snapshot, I have traded with 3 unique villagers with coal and no new trades appear.

What I expected to happen was...:

Trading with villagers for some time should have new trades appear when not all are unlocked yet.

What actually happened was...:
No more trades are unlocked and I am stuck at two trades.

Steps to Reproduce:
1. Approach villager
2. Attempt trade
3. Repeat until trade is locked
4. Exit village GUI, then re-enter to see new trades
5. No new trades appear