Shield TV 2019 (Tube) - Dolby Vision issues

I keep on having issues if Dolby Vision is enabled on the Shield (regardless if the movies is in DV or not).

Shield is connected via a high quality 1m HDMI 4K High Speed cable to a Marantz Receiver.
The receiver is connected with a similar cable to the TV but 1.5m long.

Both cables are ok, so please do not start sugegsting to buy this and that brand.

I am 100% sure about this because if I connect the Shield directly to the TV with eother 1m or 1.5m cable, all is fine and I have no trobles.

I have even tested a cheap 5m cable directly connected to the TV and it works!!!

If instead I go trhu the marantz, very often the screen flisckers, also if I am on the Shield homepage. When this happens one or a combination of the following actions work: unplug/plug the 1m cable from/on the Shield, turn Shield off/on, tuern Marantz of/on, switch Marantz to another source and then back to the Shield.

Sometimes I manage to have it working for weeks, but then a simple reboot creates the flickering problem again (like yesterday when I had to update the OS).

So to recap:

SHIELD > 1m high quality cable > TV : OK

SHIELD > 1.5m high quality cable > TV : OK

SHIELD > 5m low quality cable > TV : OK

SHIELD > 1m high quality cable > MARANTZ > 1.5m high quality cable > TV : PROBLEMS