Hi,
This is not quite Corona related, any physically based (and not only) renderer would render the same. This is about the model.
It does happen in real life too, but surface continuity is what you are most probably referring too.
If you observe the cars in real life in detail (what I used to do for a long time), there is no random bending of reflections/surface (even on cheap cars :)).
For example, as I can see from side glass, the surface is probably not well curved and is not quite continuous in relation to the front side glass.
It is all about the model and topology. There are different shaders, which can help visualize the surface flow and modeling artifacts, e.g.:
t=30s
Long story short - do not obsess over it. Just make it look right. If you go after it, you will see that there is a limit of "perfectness" you can get close but not exceed.
Check the model first, then just change the HDRI/Environment, so the flaws are not that visible.
