Why is this “unfortunate “? There is absolutely nothing wrong with Profile 5 DV and is a viable and current DV format.
What evidence do you have that shows this is somehow inferior, other than not having an enhancement layer which may or may not actually “enhance” the image, depending on what the device does with it.
Speaking of the enhancement layer, @Broncowrangler this is most likely what is causing your brightness fluctuations. I used to see this with Aquaman when playing my Profle 7 Blu-ray rips using LLDV. They ended up having to be converted to Profile 5/8 using a cool drag and drop tool I use.
I was replying to the comment that suggested Kaliedescape assumed people with non DV displays had something like a HDFury or video processor that can be used to force LLDV. Doubt its true but if so it would be unfortunate assumption.
All I wish for is to be able to force the default download to be HDR10 since I do not have a DV display and most DV downloads I have viewed did not look right or as good as the HDR10 version. I know I can force download but still seems odd to download DV when the system should know its not hooked up to anything remotely capable of DV.

