Yes, it is a familiar problem, but only very few planes suffer it. On the mosquito you at least cycle through the cannons so you know where you are in the rotation. What I recommend is to always open the bay doors, even if you intend to release from the wings. It prevents frustration and has the added benefit of the doors acting as speed breaks in the dive. Not a huge effect, but both the Mossie and the A20 can easily overspeed, so every bit helps.