I am not sure exactly what the issue is. Can you write more in details?
To reproduce this bug you should select vertical block of text from center of the window to it’s left side (1st column).
After that you should press Shift+Left. The selection goes to the right side of the window (is it bug or a feature?).
For example, assume you have some document:
Select vertical block of text from 4 to 1. Thus “1234” is selected. Press Shift+Left.
You will see that “5678” (and “0000” in the first row) is selected now. Strange, isn’t it?