...when connected with a connector.

Upvote this
https://support.keenswh.com/spaceengineers/pc/topic/custom-gas-thrusters-can-run-on-hydrogen-and-vice-versa

yeah, keen's gas system is just kind of broken; this is a long, long-standing bug with modded gases, and there's nothing we can do about it

We are running lock and loaded on our server and since the warfare update weapons are hit or miss, usually miss, as to if they auto target and start firing at reavers