I do thank you for going through the trouble to make these good discoverys.
I had some damage with a graphical picture of a pipe water burst (but no sound??). I wonder about. I had damage that was fixed. So I went to surface and the water finally leak stopped. I guess it reset as you said.
I was able to back to periscope depth without no more hull continue to show crush damage (steam, extra light blink, electrical spark but no sound), unti I went 200 feet then I got the death spiral.
So that would explain it. If you have damage to pressure hull, even though it is fixed, you still get damage some until you surface to stop the further damage and it resets. Still learning your data results.