Is it a problem if the B144 roof louvers is installed in such a way that the edge of the vent dome is above the peak of the roof?

If the edge of the roof louver's top is installed above the peak of the roof it could invite weather infiltration.

The biggest concern is possible weather infiltration. A good wind blowing from the other side of the roof will blow right into the vent. Roof louvers and wind turbines should be installed 2-3 feet from the peak of the roof.