Kodi outputting 4K regardless of display settings

I have been using Kodi for a while on an Intel NUC / Win10 computer connected to a Samsung 4K television (through a Denon amp). All the components in my system are capable of 4K, but as it causes some random problems (like screen blanking now and then), and the NUC gets a little sluggish, and I don’t even have any 4K material, I have always used it in Full HD.

Previous versions of Kodi (up to 16.1) have worked perfectly, but after trying 17.0 and 17.1 RC1, I noticed that even when Kodi’s resolution is set to 1920*1080 (at 60 FPS), the NUC is outputting 3840*2160 @ 30 FPS, according my TV’s info panel, and also confirmed by the sluggishness of Kodi’s GUI. In fact, I can change the resolution setting in Kodi to anything, and I can see the pixels getting bigger if I set it to something ridiculously low, but the TV still claims it’s 4K.

I can “trick” Kodi into actually outputting Full HD, but it only works until the next restart. Here’s the screen after booting, before starting Kodi. 1920*1080 @ 60 FPS, like it should.

I start Kodi, and suddenly my TV is getting a 4K resolution, even though Kodi’s settings claim otherwise (below). No matter what resolution I choose, my TV shows the same info (4K @ 30 FPS).

If I change Kodi’s display mode to windowed, the resolution _still_ stays at 4K. If I quit Kodi at this point, then the resolution switches back to Full HD. If I know start Kodi (so that it starts in windowed mode), the resolution stays in Full HD, and it stays there even if I change display mode back to fullsceen (below).

But this joy only lasts until the next restart of Kodi.. then it’s back to 4K.

I found some posts about Kodi issues that could be connected to this behaviour, but I couldn’t find this exact problem. I have now switched a few times back and forth between Kodi 16 and 17, and the issue always appears with 17 and goes away with 16, so I think it has to be something that has changed between the versions.

My system: Intel NUC, Intel HD Graphics 6000 (driver 20.19.15.4531), Windows 10 Home.

Any help is appreciated. Thank you in advance!