Dell XPS 9560 Shadows/Blacks and Color blocking/banding

Hi guys, have a Dell XPS 9560 4k touchscreen display. I've been hunting down every solution I could find for why in any dark areas, there is severe banding and color blocking in shadows and black. I followed all suggestions for updating intel display drivers, rolling back, uninstalling dell premiere color, reinstalling, manually adjust sliders and gammas and picking ICC profile etc. Nothing worked at all. Performed diagnostics from BIOS, everything checked out including exhaustive RAM tests. 

But I finally found something that, at least temporarily resolves the issue for me. I plugged in an external monitor through my Thunderbolt C port, and it immediately rectified the issue. Viola! Now I have smooth color and highlights/shadows/blacks rolloff. I don't know if it's a permanent fix or not, but plugging in a monitor and unplugging seems to remedy the issue right now.

I haven't seen this solution posted anywhere on the internet, so I'm posting here in case anyone else is in my situation and has tried everything. Try it out if you're experiencing this issue and see if it works for you!