Honda Navigation System

I have an Acura & the systems are very similar. First, they are made by
Alpine, not Sony.
On my dash there is a button to keep the dash lights on full bright. This
overrides the dimmer. It is for those days when the sun is setting but not
enough to trigger the Nav changeover. If you have that feature, disable it &
your Nav will function properly.
Please report back here if this solves your problem

All this speculation is for naught. There is a light sensor on the dash that
senses ambient light. This feeds the PCM which talks to the navigation
system. Just put a cover over the sensor and see if it switches the screen.
It may take several minutes as the switching can be delayed to prevent
switching under bridges and short tunnels. If you are aware of the AC it
will change blower speeds as you go between sunny and cloudy areas. As for
tracking in tunnels and poor reception areas it has a Yaw sensor built in
and that coupled with the speed sensor it keeps the map on track when
entering these areas.

For answers to your Odyssey questions got ODYCLUB.com . It is a forum of
many thousands of users and answers to almost every aspect of the van.

To add to my post you may be seeing switching from street lighted areas.