"It should be" is really not good enough answer. The the file_hash.db grow larger we can see that MAR questions over DXL times out when exeeding a certain size.
Any information on if this is fixed in any version?
Well now, considering I don't work for McAfee, my "should be" answer was out of kindness. If you care to check release notes you'll see one of the last several builds includes it in the fix. I don't recall which one it was, but 2.4.1/2 definitely includes it. I'm pretty sure ones prior to that as well.