Same here but I was prepared with oil pads. Mine no longer have that problem but I check it during the season to be sure.
Interesting. Three of our four do not have check valves after the pump. Those 3 pumps and their "Super Switch" float-arms were replaced by local service guys when we got on board the boat in 2021. All of the hose/plumbing after the pumps looks original. Haven't looked closely at the 4th... Don't think I've ever seen a "bilge design" that could prevent that last bit of water from draining back down the hose?? Four boats so far (none high-end), always that last little bit of drain-down... -Chris