Disable Ctrl+O shortcut mac

The Ctrl+O keyboard shortcut on mac is redundant, since we have Cmd+O to open files as well. This in itself isn't an issue. However, I often use the nano text editor in the terminal, which uses the same Ctrl+O shortcut to save the file being edited. Despite having removed Ctrl+O in the "manage shortcuts" menu, it persists. This obviously isn't a serious issue, but the inconsistency between Terminal.app and RStudio's terminal is mildly irritating

Anyone know of an easy workaround?

Go to tools and modify shortcuts and then you can change Any key to anything you want

I've tried removing it, setting it to something else but it hasn't had an effect. Does this suggest this is worth a bug report, or am I just being thick?