could you elaborate on this more, what you mean by "correct" breathing? Is this like "yoga" breathing we're often taught during relaxation exercises, i.e. extending your stomach while breathing?
I'll try, its not easy without a white board
Imagine your lungs as the fuel gauge on a car.
A Normal breath (relaxed position) is the mid point, exhale at 1/4 and inhale at 3/4 mark E & F are for extremes
Say you descend down a line and near the bottom you take a big inhale, to slow you while adding air to your BCD. Then exhale a bit to become neutral - you're not really neutral because you're just using the top half of your lungs. Your brain will compensate for this, until its require to think about something else and them it'll revert back to normal, and you'll sink.
The opposite can happen too.
Also you have the fight or flight reflex. The second part of which is adrenaline. The first part is that the diaphragm drops, which increases lung volume.
You don't need to be that stressed for it to happen
When people first roll in it can happen, or at a SS if buoyancy is a problem, both are diagnosed as being under weighted. On vacations people often drop weight during the course of the week because they're more relaxed.
If I'm adjusting my buoyancy at the end of a descent, I'll exhale once (relax my lungs) which takes me to the mid point, I'll exhale a second time - takes me to the normal empty and a final exhale to fully empty my lungs. My buoyancy should be neutral at the mid point of my lungs.
I make a relaxed breathing cycle, slow inhale, pause, slow relaxed exhale, pause etc etc for a normal breathing cycle -. When I first learnt, I used to mentally count the inhale, pause and exhale to get a rhythm
Hope that's mildly clear and helpful