Villager trades reshuffle seemingly randomly

After breaking and replacing a lectern to reshuffle a villager’s trades, neighboring villagers also change trades. Trying to recreate this by entering the nether, exiting and reentering the world, sleeping, and restarting the game does not work. The attached video combines two separate recordings, two minutes apart: After getting Mending (after it disappearing from the villager’s trade table due to this bug), I check the other villager and its trades are changed from one video to the other. No, I did not change it on purpose as the first one was Unbreaking III (what I wanted). The first instance that this happened, Mending became Aqua Affinity, and the relevant trade along with them changed.