SBN carb pump leak question

[Shortrun]

I am rebuilding the carbs and was checking pop off.
I decided to ckeck the pulse line for leaking, so i set the air pressure to 5 psi and found the carb was leaking, slowly, about 10 seconds to go to zero.
I tried a lot but in the end i had to make a cork gasket and with it installed no leaks now.

My picture, which is showing pop off setup, shows the gasket that was in the pump and the cork material i used.

Has anyone seen this before? Is my slow leak with the proper gasket ok?

 

[Mickirig1]

I use the OSD.com kits. He sends bolts to replace the screws. Maybe you can get it tighter for a better seal. Might be a defect in the sealing surface too.