Minecraft world that I (Microsoft) and my boyfriend (Xbox) play on that had mobs disappear

All of my sheep, cows, pigs, villagers have disappeared, this happened on November 8th 2021. My boyfriend and I have worked to gather all of our animals back since the issue was never resolved nor fixed. It is now January 26th 2022 and my boyfriend who plays on xbox and I play on windows logged in today and saw that the issue happened again, but this time our tamed animals, birds, horses, dogs, and cats have disappeared.