Apparently this isnt a bug (heavy beam cannons officially seem to do area of effect type damage, which makes sense), however it seems /very/ odd.
Before I knew of this, I picked autobombs as my special ship (ZR only), and went about spamming tons and tons of autobombs places and expected them to clear stuff out.
This being my first game since a ton of stuff went through (must be my first since v3 at least) a ton of stuff had changed. I didn't even notice tht I started with a missile silo and space dock until about 20 minutes in (hey wait, whats this missile silo doing on my planetary info?) and didn't notice I had some other weird things happening either (a ton of random bubble-looking things? oh cool they give me resources) Of course, it took until a group of eyebots appeared in a wave and blew a few up before i could do anything about it >.> (just to find, oh joy! Eyebots are immune to instakill by counterspy. grr.)
Well, seemed mostly ok, I didn't mind the autobombs not killing frigates so much, as starships eat frigates for lunch anyway, but upon building some HBC to defend a superterminal (arg, damn thing was placed on a bottleneck world. Take control and deal with both superterminal and waves ....) and a wave came through, I realized that the HBCs were completely useless at shooting frigates. Was it intentional that the end all of researchable cannons could be killed by a mere mark 1 frigate and time? It just seems odd that a cannon such as that is useless against a frigate :\