Strange behavior low light camera

Hi,
Today, while sailing with the rov, something strange happened.

On the first dive the camera worked as normal. On the second dive the camera worked normally up to approximately 1 m of water depth.
When I was 30 cm deeper the image turned black.
If I went up another 30 cm the image came back.
Even if I stayed a little longer at 2 - 3 meters depth, the image remained black, until I ascended to about a meter depth, then there was an image again.

What could cause this?