When flying the Hurricane, often when I target an enemy plane, the gunsight will disappear unless I have the HUD on. HUD off, sight gone. If I deselect (or drop) the target, it will reappear. FYI.

And now I've finally managed to reproduce it!

Thanks for noticing that it depends on HUD on/off state. This issue has been reported some time ago, but I had no idea what causes it.
Now I can see the problem and it will be fixed in one of next updates.

My pleasure and thank you.