I added the log output that you included, and these were the results I received when trying to set the higher resolution to 2048x1152 (it worked normally when setting the higher resolution to 1920x1080).
The game started initially in full-screen mode at 1600x900. I then switched to 1280x720, which worked fine. I then switched to 2048x1152, which was done and then immediately reset to 1920x1080 (my maximum monitor resolution).
At this point I switched to windowed mode and the resolution changed back to 2048x1152. Switching to 1280x720 and back to 2048x1152 worked normally here.
Switching back to fullscreen mode immediately reset the resolution back to 1920x1080. I did a little checking, and in my case this is to be expected since the Engine cannot render a higher resolution in fullscreen mode than the monitor is capable of displaying. If your monitor is capable of rendering FullHD, then it should work normally up to 1920x1080. Would you be able to provide your dxdiag information, in particular your exact monitor model? We would like to try to rule out any possible hardware conflict.