Anyone else noticed that the river currents are only correct at the top of waterfalls?

I can jump into a river, flowing whichever way you want and the current will on most occasions not be the same direction as the flow of water, at times, being diagonal to the flow. There's also areas where the current is so strong you can't swim against it, in totally flat and clam flowing sections.

I noticed a lot flow to the banks, which means stuff dropped into the water only goes a short distance before beaching. I want my slain foes bodies to go for a ride when i toss them off a bridge, not just to wash up 3 feet downriver.

Sometimes they get stuck on rocks.

Or get stuck underwater at the top of waterfalls and are never seen again.

Also my horse likes to teleport to nearby waterfalls and throw itself off when i'm not watching, maybe the crazy currents are affecting it's balance?