Both monitors are 10Bit color so bandwidth should not be an issue. Both monitors have their DP activated. Separately, they work but the moment you plug the second monitor nothing happens and only the first monitor works. Not sure if I got a defective product or what?
Club3D claims that this MST supports:
“Supported output resolution: up to 2560X1600@60Hz each monitor in DP1.2 MST and up to FHD/1080p in DP1.1 or DP 1.2 SST. Input pixel data depth 6/8/10/12 bits and supports output pixel format RGB444”