Axolotl Disappeared Even After Putting Inside bucket

My axolotls have been disappearing even though I double check to put them inside the bucket and also put them in a close up enclosure. At first it disappears when I was away only, today it happen even though I only went to sleep to skip time. I checked on reddit and multiple people (in Java and Bedrock Edition) has experience the same thing. Some even tried putting the axolotl inside a 1x1 block and it still disappeared.