I purchased this monitor from Amazon last week and was impressed with the quality of the monitor. However when I went to take advantage of the HDR feature, the monitor shows an awful issue with spotlighting and flickering. As I have come to understand the Smart HDR mode "Reference" is the only HDR mode that takes advantage of the HDR 600 VESA certification. 

When enabling "Reference" Smart HDR mode, it appears vertical dimming zones are enabled. The entire lower half of the monitor flickers and flashes when there is any horizontal movement of display content. I've tested this with an HDMI 2.0 cable connected to both my Dell Precision 7730 laptop and 4K HDR edition Apple TV.

S2719DC flickering and flashing 

This does not occur on static images and only when there is movement in the video stream. I ran the built in diagnostics and all the solid static colours and text looked perfect. So this seems to only be an issue with the local dimming on the Smart HDR mode "Reference".

Is there any way to disable this local dimming effect? This effect ruins the practicality of usage of this monitor for HDR display. The other Game, Desktop and Movie modes, which do not have this flickering effect, are too dim and do not take advantage of the 600 nit illumination and saturation which gets the image closer to the DCI-P3 colour gamut, which is the sole reason I purchased this more expensive model of monitor.

@DELL-Chris M is there anything anyone can do to assist me here?