I was playing in a community, vanilla server which has an IP of 22.214.171.124
We were shooting each other with a guy on the grassland and I go unconscious after he shot me. Everything got dark eventually and then when I get conscious again, I fall off underground and fall in the water. I start swimming in the water and never could step on the floor. Grassland was too far away above from me. There's a screenshot I've taken.
Game version: 1.10.153576