If calculated item formula contains low level discovery macro in unquoted parameter, then the trailing whitespace for this parameter will be lost if the macro value has characters that forces parameter quoting in the discovered item.

For example:
Calculated item prototype has formula str(<key>, abc{#M} ). If the macro {#M} has value (), then the discovered item will have formula str(<key>, "abc()" ), which is not correct - the trailing whitespace is included in parameter and must be quoted too: str(<key>, "abc() ").