My shulkers disappear from inventory when I'm afk

The first time I had 4 shulkers, one op and the rest were from things that I had left over, the shulker op disappeared. I said well, I'll get the other things again, not so easy, but with work, yes; A few days later (in real life) another one disappeared again and what a coincidence that it was the other op that I was wearing (the other day is today 14) the fact is that they both disappeared the second that was today was afk or that I remember the first one, I don't know if it was afk or while I was playing or watching things. In the photo appear the shulkers that when I lost the first ones I went to look for more and there they are more (they all bring things that are left over)
😞
I can't believe it I just entered the game (map) and I don't have the brown shulker