How to remove ghost players join on server

Hello, I noticed a fairly common problem on many minecraft servers that when someone enters the server, it creates as if its clone, he do nothing, has no gravity, is like {marker:1b}, only some players can see him.
I have a question how to make it not create such "fake/ghost players", the problem occurs on both non-premium and premium, is there a plugin, configuration that turns it off?

I was looking for answers in the forums but I found nothing except that this error appears probably from 1.7 to latest or something.
I am grateful in advance for your help because I have been looking for a solution to this problem for a long time.

Quote from Roman

Do you still have the problem if you turn your server into vanilla?

I haven't created a vanilla server for a long time, but it probably wasn't the case then. Can the fault be spigot? If so, can it be removed somehow because players complain about it on the server.

I know you would recommend checking the plugins but on the test server where I only have 4 plugins still creates ghost players.

Plugins on Test server 1.15.2 :
- EssentialsX (only)
- ClearLag
- BlockLocker

- SkinsRestorer