Rocket leaking fluid through outlet

I had a depot rocket transfusing oxygen to a planet. After the pipe get blocked, I observed gas leakage through the rocket gas outlet portal. It was sealing properly at the beginning, but leaks after awhile. I've also seen it happened to water and CO2. Fluids also leak out of a flying rocket if pumps are left on. Not sure if it's intended but I never had this annoyance before the shine update.