I think it may be a weakness of the automatic weightings in the camera… prioritizing F stop and ISO over shutter speed (camera presumes its not moving). It seems to sense the amount of light available… fairly dynamically and fairly well, but then applies the wrong solution.
Would a shutter priority automatic setting work better? In the past I’ve had issues with that on Sony cameras as well though… tended to jump to ISOs ~900’s.
Wish I could set automatic within limits and hierarchy… 