Could you try this file http://demo-uhd3d.com/files/uhd4k/The_World_in_HDR_in_4K_HDR10.mkv ? It’s a 60fps hdr file which Always played fine for me (before and after patch).
I’m guessing this is what your problem looks like https://goo.gl/photos/NpTcdQnh11rxzZcH7 ? (Still present with a paused video)
Or like this (video where I first play from TV and then switch to Vero input) ArrivalTest - YouTube
You can read my notes in the 10bit test thread from a while back [TESTING] 10-bit, HDR and dithering improvements - #31 by Martorias
Edit: regarding the 4:4:4, from rtings.com “After some more testing we have found that none of the LG TVs support chroma 4:4:4 when in a HDR picture mode, regardless of the input icon.”