That's a new thing for me. It worked fine for me when I tested the other day.
I think this is a limitation of the rapid deploy system, not something specific to my projects. I've had this happen before in a bunch of mods when I click rapid deploy and water cannon at the same time really quickly. The reason it does this is the Em4 hose logic gets confused sometimes. The solution is to undeploy the fire engine that triggered the glitch.