Visa date error - difference in visa dates in joint applicat

Hey all,

My parents applied together for general visitor visas (different applications, but just one set of documents submitted). My father has been granted the visa for the requested dates. But my mother's visa starts much earlier (1.5 months earlier) than my father's - her visa started yesterday. Both of them have been given 180 days visa. I presume this is just an unintended error on the part of the UK Gov. Has anyone faced this situation earlier and did they take any steps to rectify it? I have sent an email to the UK visas enquiry line. But in the meantime, I wanted to check if anyone had any advice in this regard.

Thanks in advance!