BuddyPress.org

In a decent code/text editor you would see them as additional line numbers suggesting a line feed or carriage return.

After my my closing php tag I had actually induced a carriage return which is white space which qualifies as browser output.

I did actually copy your file locally and couldn’t see any obvious line feeds / white space so not convinced it’s the issue in your case.

it is definitely in your functions.php file? you haven’t been modifying a bp-custom.php file as well ?