I was excavating an ocean ruin and I kept hearing the water flowing sound? And that sound really bothers me, so I was trying to get it to stop, but it turns out the cause is the water that was made where the blocks i broke were? You can see in the screenshot that I am in fact completely underwater.

I feel strongly that if there is a water source block above and to the side of a flowing water block, that it should become a water source block. it works this way normally, why is it not filling in properly underwater???