the vent that I am referring to is a type b vent .They have to cut their hole per local code jurisdiction. Depends on what they are venting. If it's just a bath or kitchen exhaust vent then they need to cut a hole big enough for whatever they are installing. Same with PVC or ABS
If it is a mechanical vent. ie b vent or the like, it must have minimum 1" clearance from combustibles.
So, what is the vent?
That hole would be OK if the flue pipe were centered, as is it's a code violation. Are sure it doesn't have a jack? That's the flashing on the outside that ties in with your shingles/tiles etc.It does not have a roof jack, nor does it have the 1” of clearance. But I’m wondering if the hole is too large or does that not matter?