One of the still pervasive weaknesses of mIRC script is the inability to preserve and output a sequential string of neighboring spaces. Over the years many strides have been made to allow working with sequential spaces (eg: /returnex) but the one major hurtle is doing anything to output or display strings that contain space pairs.
The most serious problem I've encountered is when encountering a file with a name that starts, or contains sequential spaces.
At one time it was possible to use $shortfn to obtain the 8.3 "old-skool" name since Windows always tried to preserve them. Formatting a drive as NTFS via Windows will no longer enable short filename support by default. And the ExFAT filesystem doesn't support short file names at all.
I've always considered this a bug. It should have been corrected a long long time ago. I know that the consequences for existing scripts could potentially be enormous, but that's a short term problem. Despite living in the short term for most of my life, we all would have been happy in the end.
I think the solution to this would be to fix the parsing engine to properly preserve spaces for /commands and /aliases and wherever else. But role it out slowly... so script developers could choose to enable it. For example: via a hidden menu option that would only appear in the "Tools" menu when the shift key is pressed.