@JakeBunny This is exactly what I tried to explain that you might be experiencing above. The issue is that the water rudders may appear to be up, and the handling in the cockpit is in the correct position, but the invisible water rudders in the physics simulation are still down. I'm still not sure what steering tiller input you're using (perhaps I'm just unfamiliar with this hardware input), but it's likely that it's turning the invisible water rudders.
Here is how I worded it in the changelog, just for different phrasing:
The water rudder may have invisibly failed to extend or retract in MSFS 2024 due to an undocumented change. Previously, users may have experienced a perceived lack of water rudder authority, or perceived abundance of aerodynamic rudder authority, depending on how the aircraft was loaded.
If you wanted to test this to confirm my suspicion, you could copy these two lines of code, replacing the corresponding "point.15", and "point.19" entries in the amphibian's flight_model.cfg:
point.15 = 5, -33.20, -5.33, -4.00, 2500, 0, 0.75, 40, 0.30, 2.5, 0.85, 0.01, 0.01, 8, 200, 200, 1
point.19 = 5, -33.20, 5.33, -4.00, 2500, 0, 0.75, 40, 0.30, 2.5, 0.85, 0.01, 0.01, 8, 200, 200, 1
