Attached --debug-init when starting -

Debian Stretch

GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11) of 2017-09-12 on hullmann, modified by Debian

Org mode version 9.1.11 (release_9.1.11-632-g60483f @ /usr/local/share/org-mode/lisp/)

However, it does not when starting emacs 27.0.50, same OS and org version

Charlie Millar