It seems to happen whenever I try to add a property to anywhere but the end of a selector.
For instance, if I have:

And if I want to add "color: red;", if I add immediately after "text-decoration", auto-complete will pop-up, and when "color" is selected, it will print "ccolor", like this:


But if I add the property right before the closing brace, it will work correctly, and I will get this:


It seems to work correctly only when the closing brace is on the same line. If I insert a property before "color" now, it will work. But if I insert a property after "text-decoration", it will fail again:


I hope this is sufficiently clear!