Where’s the bug? The damage profile breakdown shows the same thing. It just has better carapace damage on lights. Dunno if it’s good balance but there’s no reason to think it’s not intentional. It’s not unique in this either, a couple weapons do that.
That really depends on your assumptions around what a “heavy attack” is. It doesn’t mean it’s got more armour pen it’s just a different move with different utility to the light attack.
Because both heavy 1 and light 1 attacks are strikedown attacks, and heavy 1 does more damage to every other armour type than light 1 does.
Fatshark definitely took the wrong lessons from the feedback last time they ‘fixed’ it, they made light attacks weaker all round while the heavy attack on carapace remained exactly the same, then they reverted it back to what we have now when they heard, “not like that”.