If someone has a problem with getting null component, even when it's for sure attached to the entity

Hello.
I had such a problem:
I have created the component, then attached it to the entity.
But when I tried to get this component in code it all the time returned me null.

Here is the solution, I have accidentally found:
- Press "Dots->ClearEntities"
After that step by some unknown reason, the editor can begin to emit errors concerning the impossibility of displaying information in [Inspector] or [Animator]
- Then close editor
- Delete [GlobalEntitiesDependencies], [SceneDapendencyCache] and internal of [Library] folder.
- After reopening it helped
But this error emission can occur again
- Then after deleting [SceneDapendencyCache] and reopening the project it dissapeared.

Error and solution were discovered using these packages(1*) and using Unity version: [2020.1.11f1]
Screenshots of errors(3*) will attach later if they will occur again (forgot to save them).

 

Here is this component(2*). An error occurred in the [release] build in the browser. Build I use (4*).
After each build, I clear all cache in the browser.

 

Now I finally got this error again(3*). It can occur after reopening the project. But when I close and try to open it again it can help to solve this error. Because of this error I can only see: Scene hirerarchy, Project folders, Scene window, Game window. Other just in flat gray(or black - depending on theme) color.
So I think the solution, maybe, doesn't depend on this step:
"- Delete [GlobalEntitiesDependencies], [SceneDapendencyCache] and internal of [Library] folder."