Looking through the simulation, the only difference is the mesh at the moment. I inspected your geometry, and the first geometry meshed relatively well due to the reduced complexity despite the geometry not being waterproof. In essence, you may have gotten lucky with the first particular geometry/mesh.
For the second and third geometry, the same issue persists where the geometry is not watertight. With the added complexity of the front wing, the errors within the geometry are “magnified” and this likely translates to the mesh which gives rise to the divergence seen in your simulation.
The fix now would be to fix the geometry to ensure it is watertight and apply best CAD practices to ensure a high quality CAD model for meshing. The mesher (SnappyHexMesh) is a iterative mesher and requires a good quality, defect free geometry to build the mesh upon.
Do adjust the geometry, re-mesh and try to simulate it again. Let me know what the results are.