When swimming, the screen turns black

Following the update this morning, I didn't play much, just browsed what the update was for--

I decided to play properly and was blown into the sea by a creeper, to which the whole screen turned black when my character's head went underwater - with only the toolbar, health/hunger, coordinates and bubbles on the screen. (See attached screenshot).

I "Save & Quit" my game and went back to see if it happened again, which it didn't so it must have figured itself out but I thought I'd report it anyways.