problem: /usr/share/vim/vimfiles/plugin/bugsummary.vim installed with vim package specifies the normal mode mapping: nmap <Leader>bug :call <SID>FindGetBugSummary(getline("."), col("."))<CR> which can conflict with the user's local mappings. In my case, this mapping adds a delay to my <leader>b mapping which is used for another plugin. Ideally, such system-wide plugins should not add unsolicited mappings and instead rely on the user to set them if and when desired. temporary workaround: add ~/.vim/after/plugin/removemapping.vim with the following content: unmap <leader>bug possible solution: remove the mapping from bugsummary.vim and allow the user to set any preferred mappings in .vimrc or elsewhere.
The file bugsummary.vim isn't shipped anymore (Vim 8.0 or gentoo-syntax). We can close this bug.