Which is more accepted or more common, “for some reason” or “for some reasons”?

Question

I often hear native speakers say for some reason, but I think reason is usually a countable noun and "some reasons" can have the meaning of "an unspecified number of reasons". I think for some reasons ought to be a correct form of it.

What's your comment?

Is "for some reasons" used in everyday English? If it is, what's the difference between it and "for some reason"?

(The answer to the question that people think is a duplicate of mine doesn't help, because it lists both singular and plural words used with "some".)

Answer 1

SOME (determiner)

1. of a certain unspecified number, amount, degree, etc:
   "For some reason, I don't think this is grammatical."

Some is being used in the same sense as unknown. Being a noun starting with a vowel it is modified with the indefinite article an. So the meaning is "for an unknown reason."

In casual conversations you will commonly hear the redundant: "For some unknown reason."

Answer 2

"For some reason" is the natural way to say "for one or more unknown reasons."

"For some reasons," like "for some one reason," are unlikely to be said because these phrases imply that the reasons are known. Already noted in a comment:

The phrase "for some reason" is saying "for this reason or that reason...", and only refers to a unique reason, so the singular reason is used. If there are multiple reasons, it has to be taken in context. -- user3169