This may well be an en-gb locale specific bug. Also, who's mum charges rent?
My mum didn't charge me rent, she charged me a ... "contribution".
However, once you're done with your education entirely, unless there's extenuating circumstances like severe disability, you absolutely should be mostly paying your own living expenses, even if you're living with someone else.
https://www.onefamily.com/talking-finance/finance/should-you...
> According to a survey by My Job Quote people over the age of 18 and living with their parents pay on average £230 per month to their parents in rent – 65% less than the £690 median rent in England in 2018.