Is "raises question marks over" a correct and common phrase?

Solution 1:

I agree, "raise questions over" sounds better than "raise question marks over" to my British ears.

We can search Google Scholar "to broadly search for scholarly literature" with each phrase.

• "raises questions over" has about 1,940 results.

• "raises question marks over" has about 61 results.

Solution 2:

"A Question mark over" seems to be veritable idiom according to this source:
http://idioms.thefreedictionary.com/a+question+mark+over

It can be used in many ways as in

• "A question mark hangs over something" or
• "This leaves or puts a question mark over something"

It seems to sound off better than "leave question marks over something" , at least to me.