This is bisected to b6b509b (which 467f7ff claims to fix, and indeed does partially)
Reproduce by doing: emacs -q -L /home/youngfrog/sources/org-mode/lisp/ -f org-mode --eval '(insert "<2012-02-27 Wed.>")' => timestamp is not fontified. or instead emacs -q -L /home/youngfrog/sources/org-mode/lisp/ -f org-mode --eval '(insert "Whatever\n<2012-02-27 Wed.>")' => timestamp is fontified but fontification is lost if you hit RET I tried to patch but didn't succeed. The newline (or beginning of buffer in first case, but that's probably unimportant ?) seems to be the problem. Any idea on that ? -- N.