The refspecs specified in the .git/remotes/<remote> on the "Pull: "
lines are for fetching multiple heads in one go, but most of the time
making an Octopus out of them is not what is wanted. Make git-fetch
leave the marker in .git/FETCH_HEAD file so that later stages can
tell which heads are for merging and which are not.
Tom Prince made me realize how stupid the original behaviour was.