Sulfur cubes despawn even when name tagged

Hi!
Thank you for your report! 

Could you please provide more details. As we have no repro of this issue.

• Could you please record a video of the issue and upload it?

• Did this issue occur on a LAN or on a multiplayer server?

• Could you try performing the issue on a flat world?

Quick Links: 
📓 Issue Guidelines – 💬 Mojang Support – 📧 Suggestions – 📖 Minecraft Wiki

I had the same problem. I don’t have a video, it was in single player, and my world was not a flat world. I went about 600 blocks, and when I got back, the 2 baby sulfur cubes had despawned. I named the mob went it was a big sulfur cube, but accidently split it in 2, so I trapped it and decided to wait until it grew up. when I got back, they had both despawned.

(Sorry for the extra details, I don’t know what info is useful)

This also happened to me, but this only happens with the baby sulfur cubes.

Hi!
Thank you for your report! 

We've already resolved this issue at MC-308361, so I will close and link this ticket as a Duplicate. 

Quick Links: 
📓 Issue Guidelines – 💬 Mojang Support – 📧 Suggestions – 📖 Minecraft Wiki