Wandering Traders may repeatedly sell Pale Oak Saplings.

Steps to Reproduce

1. Download the world below and join the world.
2. Kill the Wandering Trader that already exists in the world.
3. Place a redstone block under the Repeating Command Block.
4. Wait until the command blocks stopped working.
5. Open and watch the trade menu of the wandering trader newly summoned.
6. You found that the trader sells two items both are pale oak saplings, but the command blocks did nothing editing the offers.

Note that this issue influences Villager Trade Rebalance the experiments, too.