Well... the phrase "It is I" instead of "It is me"
Saying "It is I" is still wrong, and it only ever done to parody someone who is overly dramatic (like Leclerc in 'Allo 'Allo). The flub appears to have been fixed now though, but I would suggest they get someone to proofread the text before release.
"It is I" is older and more consistent grammar.
"It is I who killed the butler!"
"It is she who killed the butler!"
vs. "It is me who killed the butler!"
"It is her who killed the butler!"
or "It is them who killed the butler!"
Relevant formal grammatical concepts are subject vs. object pronouns, and copula verbs ('is') vs. prepositional use ('living with')
Granted, if there isn't any trailing part, then "it is me." or "it is her." have come to sound more natural than "it is she" or "it is they." (ouch)