Roof vent placement over rafter

I found this on a recent inspection. Looks like a roofer (or homeowner) decided this was a good place for a vent. No indication of water penetration was observed, I haven’t found any documentation that its a defect. I noted it in the report advising monitoring and repair if water penetration should appear. Any help on comments would be appreciated.

seen often on new construction in the Dallas/Ft. Worth market
roofers or some other trade install vents/jacks after shingles have been installed
blades are expensive & sawing on some of these steep slopes is very dangerous probably taught to do it this way
dragging a saw, extension cord & misc tools is labor intensive for many
easier for some to hack the osb to fit the vent

http://www.fishertools.com/images/products/5/5276/a9813d187362cbc096aac2109d054ae3_200.jpg

doubtful it will diminish air flow enough to have any great negative effect

That is a very common location for a roof vent. It is not a defect.

If the vent wasn’t over a rafter, would you have said monitor for leaks? Flashing is what determines leaks, and if that was OK I wouldn’t have said that.

The ventilation is restricted because of the rafter, but if there are others that compensate, it should be OK.

What kind of saw makes that good a cut. I want one. LOL
Kidding aside, I agree with Joe.

You probably already have one, it’s called a hammer.

Thanks for your comments, much appreciated.