White Rabbit

I didn't have to erase my cloud saves, I just had to disable it for Minecraft then it let me upload. I did reinstall right before, and it didn't let me upload. I also tried moving the data between the SD and built in storage with no luck. Very frustrating issue.

I don't have this issue, but have been dealing with REALMS-8022 and am finding it may be something to do with the Nintendo cloud save backup. You guys might try disabling it for Minecraft and see if that helps?

I've been having the same issue. Reinstall didn't help, but what I did find to work, is to turn off Nintendo cloud save game backup for Minecraft, then I could upload my world to the realm. I turned the cloud save back on now, but my guess is that the cloud save trying to update is somehow messing with the storage limits for Minecraft that it thinks the "HDD" is full.