extra space at the end of lines in source

[Greg Minshall]

hi.  i can't date it exactly, but in the last week or so, editing a
source buffer (with =C-c '=) adds spaces (to the "tab location") of
previously blank lines.

i.e., the second line in each of the following source blocks is empty,
but if i =C-c '= then =C-c '=, each will end up with a few spaces on it.

#+BEGIN_SRC R
  cat("hello, world\n")

  23
#+END_SRC


#+BEGIN_SRC bash
  echo hello, world

  echo 23
#+END_SRC

i'm running
: Org mode version 9.4.6 (release_9.4.6-559-g5e4815 @ 
/home/minshall/.emacs.d/straight/build/org/)
via
: emacs -Q --eval "(add-to-list 'load-path \"~/.emacs.d/straight/build/org\")" 
foo.org

any thoughts?

cheers, Greg