I was playing on a creative/survival world testing a mod and when I went to add an effect to myself I found an odd string in the possible entities. I investigated more and found that only an entity close to you can be referenced this way, and only sometimes, but this could also be wrong.
MC-255860
Entities can be referenced by string.
Resolved
Invalid
0
You mean the UUID suggested in auto-complete in commands? It only suggests the looked at mob's UUID. Also, entities need to be loaded to be targetted; go too far away and they unload.
There's no bug here.
Also, issues with modded versions are not accepted here.