Bash sources profiles

[docunext]

   The following paragraphs describe how bash executes its startup  files.   If  any  of  the
   files  exist  but cannot be read, bash reports an error.  Tildes are expanded in filenames
   as described below under Tilde Expansion in the EXPANSION section.

   When bash is invoked as an interactive login shell, or as a non-interactive shell with the
   --login  option,  it first reads and executes commands from the file /etc/profile, if that
   file exists.  After reading that file, it looks for  ~/.bash_profile,  ~/.bash_login,  and
   ~/.profile,  in that order, and reads and executes commands from the first one that exists
   and is readable.  The --noprofile option may be used when the shell is started to  inhibit
   this behavior.

[grant-humphries]

I'm not sure this will be reviewed/merged anytime soon, as it seems this project is no longer being actively maintained, but per documentation that you cite above the line:

source /etc/profile

should be removed as well as bash already loads this file when invoked as a login shell.