Some circumflex letters do not work, such as â and î. æ doesn't work either (Colemak, perhaps other layouts as well).

[krompus]

In Colemak, you attain the circumflex by hitting AltGr+x and then the letter you would like to apply it to.

î is attained by hitting AltGr+x and then i.

â is attained by hitting AltGr+x and then a.

æ is attained by hitting AltGr+z.

I noticed the issue when trying to type in French just now.

I tested all of the French accented characters with vim-rsi disabled, and again when enabled. These are the only three that are affected, and every one of them functions correctly without the plugin enabled.

I haven't tested these with any other layout, so it is unclear if other layouts are affected. It's possible that it has something to do with how they are composed in Colemak.

[justinmk]

6 similar issues are open: https://github.com/tpope/vim-rsi/issues?utf8=%E2%9C%93&q=is%3Aissue%20is%3Aopen%20meta

Obligatory mention that this problem does not exist in neovim.

[krompus]

Oh lovely.

Maybe it's time I finally switch to neovim then?

[lacygoill]

I can't reproduce. It was probably fixed by ad8ba6b.

See also this answer on vi.stackexchange, to see how the issue can be avoided in Vim.