RoyalKing: Yes, the Dell display via the DVI adapter->DVI works just fine.

We also tried only having only one of the Samsung screens connected which gave the same error.

Finally we tried an antique Dell 2007WFP from god knows when, much older than the Samsung screens and that didn’t work either, when using the native 1650×1080 resolution. Setting the resolution to a lower one, just for the sake of testing, gives image but like we first saw on the Samsung as well, the image is not aligned to the actual screen boundaries.