For what reasons does the file syntax setting disappear in the editor?

Question

Code editor

Greetings.

Many times I noticed the disappearance of the syntax binding to files: I opened the editor (sublime, atom, vscode), set the desired syntax for the file (the file without an extension, is not automatically detected), after some time I open this file, and the syntax in it, for example , changed from "HTML" to "Plain Text". This little surprise in the display is annoying.

If you have come across this, know what could be the matter and how to avoid it, I will be glad to recommendations on the case.