I finally found the appropriate contact number at the Home Office for this query, they told me that there is no need for her to change her name on her residence card as it's EEA. She just needs to bring marriage cert when travelling as evidence of name change on her passport.

My wife, non EU citizen, is the holder of a EEA family member British residence card. We both live in the UK, Irish citizen myself. She recently renewed her passport, and changed her surname to be the same as mine. Her residence card still has her maiden name. I'm struggling to find online if she is...