I just don't know, and I don't have any lenses anything like that lens here to test at the moment
My only suggestion is try setting that dial with the numbers 22 - 16 - 11 and so on to #8 and try taking another picture again.
Here's the tough part. You must have the camera set to Manual for that setting to work right, otherwise it'll stay on the 2.8.
Which is often a very soft setting on a camera, which could be mistaken as out of focus.
You might also want to set it on a table or better yet a tripod for this test with the SR button turned off.
If the pictures still look like that send it back