Teleportation to underwater should cancel active water walking effect
In OpenMW, "Recalling"/Teleporting to a "Marked" location underwater (any place where you can't cast water walking effect to be clear) doesn't work while water walking effect is active, it's because the player character gets teleported to the water surface immediately instead of the marked location that's underwater.
Morrowind allows recalling to marked locations underwater by canceling the effect, even if the PC was wearing an enchanted item with Constant Effect water walking; it will still cancel it (you have to re-equip the item again once in water surface or on land to re-cast it like usual).
Btw Recalling to a marked location in a water surface area while water walking is active works fine in OpenMW (like in Morrowind.exe), the PC will be water walking immediately.