This may be totally intentional, but wasn't specified anywhere ? The main post does state "Semi-Auto Fire weapons only", but doesn't account for trigger-switching weapons. Unless stated otherwise by DE, this is indeed a bug, or an oversight. If it's intentional, please lock this.
So as the title says ; the new Semi-Auto fire mods cannot be equipped on weapons such as the Fulmin, or any Incarnon (rifle, shotgun, secondary) that changes trigger-type.
That's about it, HF on the new