I have seen a couple of these reports already here on the forum (for example https://forums.factorio.com/123146)
The end result is that some asteroids will eventually slip through the railguns defenses due to shooting speed and target priority limitations after you just let them run for long ...

That's a nice ship, I also like designing my own so I try not to look at or take from other peoples ship designs too much, but the idea of having slightly different target priority rotations is something I will definitely add to my ship designs from now on, maybe it will be effective, curious to ...