Yes, “Change monitor” is set to “ALL”. After restarting remote computer the behavior changed. Now, I see both remote screens side by side which is ok, but “Resize remote screen” still does not work thus remote screens are being displayed on one big canvas with resolution of (1680+1920)x1200.
After choosing “Resize remote screen” for a few times while connected I see some graphical artifacts on the remote screen as if the process of resizing was started but in the end screen is not resized. Subsequent use of “Resize remote screen” option has zero effect (not even graphical artifacts are visible) which suggests remote system “stops” listening for resize command/event. I could record the whole process if desired.