Supporting Fire skill disappeared

Experimenting with Tactician's Supporting Fire, I unfortunately unchecked both weapon sets for the skill. It instantly removed the tab I was in ("command" for Supporting Fire), so I can't check it back. It also removed skill from the action panel, so I can't use the skill either.

I tried restart / respec in and out, but the skill does not come back. Seems like I permanently broken my character, as it is main skill for the build. Can I get it back please?

UPD. Changing server helped for some reason.