That is why I asked for a script that 1) Creates a list of variables. I already tested /unset, including your above alias, and cannot reproduce any issues with the list of variables that I have.
Looking at the image you provided, it looks like you may be using /set with text that contains $cr and/or $lf characters? You cannot do this since /set does not support that. You should store these types of lines either in binary variables, in files, or encoded in some way.
