Hi,
only recently I use Monaco editor but I have this "problem" and I try to explain ...
Often happens that when I try to place the mouse pointer at the beginning of a line, It's like that line is disabled; it's necessary to click into another part of the code (sometimes two time) and only after I can place the mouse pointer into that line ......
Rather than saying you have already provided the information it is better to repeat it in one place. Also it was not clear from your post whether the working one is the same system as the failing one.
Are you serious?
Anyway I appreciate always the help that you provide (free) in this forum and for this I thank you but evidently is not a good day ....