Bing carb breather/over flow

I've got the same problem with my right carb on my 912ULS. This started happening immediately after I installed the carbs after being rebuilt by Rotech (Canada). This does not appear to happen when the engine is not running. If it is running and I turn on the electric fuel pump, it spits fuel out of the air intake side (I guess). Electric fuel pump delivers around 3.8 psi when the engine is not started. I have a manufacturer installed air box between the carbs with a single air filter. The air box is slanted down on each side with two drain hoses (one on each side for each carb). One of these hoses spits out fuel. I mentioned this to Rotech and they said that they pressure test the float valve by turning the carb upside down and apply 7 PSI of air pressure. They said it passed their test. I've synced both carbs (mechanical and pneumatic) using a digital Carbmate and have 0" differential pressure at idle. I can't figure out why it is doing this. Today I decided to fly for an hour without using the electric fuel pump during take off/climbs and when I parked the plane for about 30 minutes it had a puddle of fuel underneath the plane. It did not spit fuel while exiting the aircraft after the flight, but I suspect that the fuel is heating up under the hot cowling (without any air flow to keep it cool) while it was standing there for 30 minutes and the fuel in the float bowl is expanding and finds it way out the drain. I never recalled it ever doing this before, so there must be a common problem. I'm at a loss as to what the issue is. Any comments or suggestions?