I’ve been on 2019.1 for a while, so I don’t know if this is unique to 2019.3, or if it’s also an issue in 2019.2. But I created a new scene in an HDRP project, and got really confused why the lighting was so weirdly dark or blown out depending on the angle of the camera in the scene view. Eventually I found that these days, there are HDRP scene defaults that take effect if you don’t have a global volume in your scene, and one of those default settings is dynamic exposure. This looks really bad in the default scene if you, say, just add a single game object to the scene. The dynamic exposure will take input from the skybox, which is extremely bright and dark at different places.
To reproduce, just create a new scene, stick a Cube in it, and look at the cube from various angles.
This is probably less of an issue once you fill in the scene with lots of geometry, but I can see this being really confusing to someone new to HDRP. Maybe you could consider not including this in the defaults.