Gfx Device Resource has already been registered

Since I updated to Unity 6 (from Unity 2021.3) I have that assert now and then in the editor.

It is usually followed by that one:
Failed to insert tex to TexIDMap

There’s no stacktrace at all so it doesn’t seem to come directly from my code.
I know it comes from something in my project, but I have no clue about what it could be.

Does someone could tell me what these asserts mean and the usual situations where they appear?