Found by Simo and patched by Volker. Patch for 4.0.0rc to follow.
Created attachment 7954 [details] git-am fix for 4.0.0rc.next
Re-assigning to Karolin for inclusion in 4.0.0rc.next. Thanks, Jeremy.
Pushed to autibuild-v4-0-test. Closing out bug report. Thanks!