Can't get exclude to work

[LeavOA]

Using windows powersheel, I'm sending the command:

'.\rfm.exe backup -domain 192.168.1.6 -exclude gcodes ".\backup 2020.10.10" "/"'

However the script always backs up the gcodes folder, no matter what I do.

I've tried:

-exclude gcodes
-exclude "gcodes"
-exclude "*gcodes*"
-exclude "/gcodes"
-exclude "0://gcodes"

the help file has a mysterious asterisk in the command, but I don't think that is part of the command:

Usage: rfm backup <common-options> [-removeLocal] [-exclude <excludepattern>]*
                  [<local/path> [<remote/path>]]

But I tried
-exclude "gcodes"*

anyway, to no avail ofcourse.

would appreciate guidance on this.

Thanks!