I'm afraid I found a very disappointing reason for the footnote problem: http://osdir.com/ml/help-texinfo-gnu/2015-09/msg00003.html
Apparently, emacs 24 interprets anything which looks like (1234) as a footnote. Given this, I'm not sure anymore whether it's worth trying to produce texinfo documentation for sage, because having something like (3) is very very common in the documentation. However, this doesn't explain why info jumps to bad places - again, this seems to be an emacs, not an info problem. any ideas oor suggestions? Martin
