Floating next to water

If i stand next to water i start to float but it only happens in this position.

I am standing on black carpet on top of a dark oak fence with a spruce slab, spruce planks  and water next to me.

I'm running:

GeForce RTX 2070 gpu, i5 8400 processor and 16gb memory.
Windows 64 bit.
1.15.0.9 RTX beta