The type is optional, so that this should not be required.
See https://docs.phpdoc.org/3.0/guide/references/phpdoc/tags/param.html

If you're using a parser that mandates the type, you might want to open an issue there.

Yes, the type is optional.
But omitting type is not consistent with Symfony codebase.

So I don't know a reason to not specify it.

I would say that the Symfony code-style is to not duplicate into phpdoc info that is already found in the signature.
We cleaned up a lot of phpdoc thanks to php8 on branches >= 5.4.
I'm closing therefore, thanks for submitting.