Help understanding unexpected diff output

Hi!

I hope we all agree that diff should make our lives easier, so here is something where I think it does not apply:

I inspected some changes using "git diff", and it was hard to me to find the actual differences (see git-diff-png):
I had to look a long time at those olcAccess lines to find any difference, so finally I pasted both blocks into separate Emacs files a and b  (via PuTTY) and used "ediff-files" (see diff-emacs.png).
Within there, the was only a part of one line changed!

I don't understand this. I had even used "git diff -w" to ignore space changes (which aren't expected anyway).

Any ideas what might be wrong and how to get better diff output?

(git-2.26.2-27.36.1.x86_64 of SLES12 being used)

Regards,
Ulrich