I have two screens, and the problem occurs on only one of my screen.
Furthermore, on the screen where the problem occurs, depending if I quickly take the screenshot or not, the pink area will either fully cover the screenshot or for example only 90% of the area if I click-drag and release mouse button quickly...
Issue present on my system :
Ubuntu 17.10 64-bit
GNOME Shell 3.26.1
Linux Kernel 4.13.0-32-generic
I noticed something interesting and that might resonate with comment #31 above (https:/ /bugs.launchpad .net/ubuntu/ +source/ gnome-utils/ +bug/743176/ comments/ 31).
I have two screens, and the problem occurs on only one of my screen.
Furthermore, on the screen where the problem occurs, depending if I quickly take the screenshot or not, the pink area will either fully cover the screenshot or for example only 90% of the area if I click-drag and release mouse button quickly...
I can provide more information if needed.