Hello, I have a minecraft hardcore world called "Quarentena" that I've been playing throughout 1.16 snapshots, and today I saw a bug and I don't know how long it has been there, but I think it's since 20w17a. The bug is that the world stops being a hardcore one and transforms into a normal one, the hearts become the normal ones and I am able to change de difficult (it's on hard and I can change it, but it shouldn't in a hardcore world). The world also goes back to hardcore after quitting it and coming back but it's no guarantee, since once I even restarted the computer but the world was still transformed into a normal world. I will send four screenshots; The first is showing the world menu and that the world is a hardcore one,; The second I took back in April 23rd and I didn't notice the bug and was just screenshotting my buildings, but looking for the screenshots I noticed that the hearts weren't hardcore ones (all the screenshots before this one the hardcore hearts were there); The third  that I took earlier today, April 26th, because of the rain bug and I found it funny (hardcore hearts were there); And the fourth one, that I took today around an hour after the third, that I realized that the hearts weren't hardcore and I could change the game difficult. I restarted the computer but the bug was still there. After some quits and backs the world was hardcore again, and I went for a backup, after the backup I went in again to find the bug there, again.