Opened an existing world that was spawned/ seeded in 1.16.  My nether portal is located at 900 65 -905.  When I went through the portal, I spawned in the nether at 900, 87, -905.  The portal in the nether is located at 105, 58, -115.  It took a very long time to get back.   When I finally found my portal, I went back through the portal to the over world and spawned at 105, ##, -115 which was in the ocean and again no portal was nearby.  I tested this in my world that was created in beta 1.17 which is behaving as usual.