If you have two beer pumps but only one is connected and the gas runs to both, will it leak
When you say one is connected do you mean “in use”? There should be a shut off valve to switch off the supply of gas to each gas pump. However if you mean you have one gas regulator feeding two gas pumps then you should call tech services to isolate the pump that isn’t in use. If not you could get an airlock in that pump and it will keep pumping till the gas bottle is empty.