Official comment

Update January 20: The new version with the Auto Exposure, Shutter Priority and Manual exposure modes has been released.
Sooo... We switched to using Shutter Priority Auto Exposure for the latest version. The problem with doing that seems to be that it is taking the last used exposure to lock on to and if that exposure was a long one, the aperture cannot stop down enough to cut out enough light to keep it from being over exposed. While this has only happened for a few jobs we have seen posted in the system we are certainly concerned with it and will find a fix. It appears the problem is that Map Pilot does not enforcer a defined starting point to lock the exposure time (shutter speed) to and simply uses the current setting.
The workaround for the time being would be to set the exposure time to 1/250-ish in the Go app, close it, and then open Map Pilot. This way Map Pilot should inherit the more appropriate exposure time value.
That being said, ALWAYS CHECK YOUR DATA!!! We always do a quicky map to test things out before taking real data.
There are ways to keep Lightroom from plowing your tags:
https://helpx.adobe.com/lightroom/help/metadata-basics-actions.html
It recently took 13 days to get through app review and we aren't totally sure where to set the starting point yet.