I'm not 100% on the mechanics behind this, but I'm relatively sure this phasing is possible with other weapons, small lasers were just the easiest to reproduce. I've had this glitch happen to me before with heavy lasers too, but I've been unable to reproduce it with them even in about an hour of testing.
While not "game-changing", it definitely gives all affected weapons an advantage they are not supposed to have, so I thought I'd bring this up
I've attached a save game with a small laser kite and a Sprocket that's getting its deck cannon killed through a layer of armor, and a couple gifs of the glitch happening to me in that test game as well as normal career games. It's weirdly inconsistent, but I'll continue investigating and post all my findings below.
The save game may say that mods are being used, because I was using a mod to increase the zoom level to make the hitboxes in the first gif at least partially visible.
While my initial tests (and the career gifs) were on the latest release candidate (0.28.1_rc2), the bug exists on stable as well (the last gif is on stable release 0.28.0f).