Iām having the same problem. Xbox One Bedrock edition for me.
Aha, yes; I had both Natural Texture Pack and Clear Craft activated. I think the problem is with Clear Craft. For some reason it shows two versions of Clear Craft (one says 79.4MB and the other 91.2MB; I assume 91.2 is the newer one) in the realm settings and it won't let me remove just one of them. It shows only the newer version on a world apart from the realm, but the Piglin issue still persists anyway. So I am unsure if it's the old version possibly still active, whether it shows in the settings or not, or if Clear Craft altogether is the issue. And yes the issue goes away without texture packs, so I may just have to get used to playing without Clear Craft or ignore the Piglin issue as I don't see a way around this. Thank you both.
I just had a horse mysteriously disappear from a fenced area when it had a name tag, a saddle, and was wearing DIAMOND armor. It exceeded the criteria to not despawn, and what happened? It still did, along with the diamond armor...