rvm.fish fails because of color-related vars

I have some vars in my env that make the script choke:

    rvm_error_clr=
    rvm_notify_clr=
    rvm_reset_clr=
    rvm_debug_clr=

They seem to be related to color-coding rvm output. When I remove them, the env gets updated correcty. Otherwise, I get the following error:

    fish: Tokenizer error: “Unexpected end of string, parenthesis do not match”