Question: f/45 on Micro Nikkor 105 VRII???

I recently shot a close-up image of a hardware connector for work.

This was shot with a D800 and a Micro-Nikkor 105mm VRII, tripod mounted. I stopped it down to its maximum, but didn't really pay attention to the settings (I was under deadline pressure.)

Later, I noticed the EXIF data had recorded the f-stop as f/45. I'm baffled, as I thought the 105mm VRII's minimum setting was F/32. Anyone have any ideas on this?