ToME: the Tales of Maj'Eyal

When selecting the Mecharachnid as current played character Gauss Cannon doesn't do anything when used. I can cast it, it's usage is noted but there's no damage. Same happens when piloting it via Mecha Piloting.

I'm playing on an Adventurer an with some addons, so I might have to do some more testing if it's not replicable for others.
Cheers!