Why would a uni ask for a reference 10 years ago?

Just need a little advice.
So I’ve applied to do my MA in Social Work and was given interviews/assessments for all 5 choices.
I declined 1 as I realised I didn’t actually want to go that far.
I attended UEL interview first and in 2 days was given an offer.
The next was London Met which i was unsuccessful in my interview but wasn’t too cut up about it as I actually didn’t want to go there ( used it more as a back up).
Lastly I attended middlesex University interview which went better than the others apart from two questions, which I stumbled upon but it is actually the University I want to attend.
I was informed that the decision would be updated by UCAS 5 to 7 days later.
However, today I received an email from the admin team asking me to complete the suitability form which I have now done but to also provide an additional reference.
I was a bit confused as I provided my most recent academic reference from my BA honours in education studies, which was completed in 2019 and have always used the same referee, and graduated with 2:1. Therefore, I asked Uni if there was an issue with my academic reference or whether they needed me to provide a work reference.
I gained a response from the admissions team stating that the tutor actually wanted me to provide a reference from when I studied my BSC in nursing mental health, which was also at Middlesex University, but over 10 years ago.
I am a little confused as to why Middlesex would like me to provide a reference for a course that I studied at their University 10 years ago, which I also didn’t complete due to personal circumstances at the time. In the last 2-3years I have actually applied to Middlesex to do other courses and have been successful gaining interviews but unfortunately didn’t mean the conditions of my offer to enroll on to the course.
Please can anyone shed any light as to why they would ask me for this additional reference?
I suspect they wanted to make me an offer, but needed to clarify a few things. However, I have never come across any Uni, asking for an additional reference if one was provided via UCAS and especially after being interviewed.