This is a limitation, not a bug.
There's a workaround you can use for files:
hi <3 spaces> test.txt contains "this is a test that worked"
The following successfully reads the file:
//echo -a $read($findfile($mircdirambience\,hi???test.txt,1),n)
To save using $findfile every time, you could use this:
var %file = $findfile($mircdirambience\,hi???test.txt,1).shortfn
You can now read the file using $read(%file).