I'm 80% sure that the problem you are having can be fixed by going into the cogwheel of that action and set the flag "Process Nothing". Your \f needs to be stopped being interpreted by KM as a linefeed, which you can read about on this page:
To include a percent in your text, simply double the percent (%%). To include a backslash \ in your text, double the backslash (\).
So:
You don't always have to escape the \ -- as you saw with your \m, if what follows can't be interpreted as "special" the \ will be treated as a literal character -- but it's good practice to always escape it so you don't get caught out.