That pretty much says it...God, this reporting Bugzilla thing is a pain! It's worse than working in Wikipedia!
On pc Debian x86-64 with master sources updated yesterday, I could reproduce this. I don't know if it's a bug, an enhancement or the fact that "Insert" doesn't appear is on purpose. Any thought? Anyway, here's a code pointer: http://opengrok.libreoffice.org/xref/core/svx/source/stbctrls/insctrl.cxx#74 webistrator: if you want Bugzilla improves, you could detail the problem. Since we try to have 1 problem/1 bugtracker, I suggest you to create a new bugtracker, I think it might be easier now since it won't be the first one ;-)
Bimodal for Insert/Overwrite is by design, changed May 2012 with http://cgit.freedesktop.org/libreoffice/core/commit/?id=b30e202861e9bdba4d86e76ba8a6f059da8efc31 Have open UX-Advise issue on what to do with UI for the the Insert-Overwrite/Caps lock/Number lock mode on the status bar as bug 88296. *** This bug has been marked as a duplicate of bug 88296 ***