I have a mapping for <C-o> in insert mode set to <C-w>. So many insert mode mappings don't work because they are setup with imap, instead of inoremap. I changed it everywhere I could find, but you'll know better.
Please feel free to accept this pull request or address this issue in any other way you see fit. All I ask for is to use [isvn]noremap instead of [isvn]map.
Use *noremap flavor commands to create mappings.
Thanks for the suggestion, I merged your pull request.