"Unsmooth" colors in color gradients in videos? Tonemapping issue?

[SodR]

Hi I have noticed that when there is a color gradient visible in playback, specially when the picture is going showing a gradient into a dark area. I guess this has to do with HDR tonemapping and transcoding? Is there any way to fix this to make it smoother?

See the attached photo for what I mean. Often this is even more prevalent but this was the first video I opened.

Thanks.