UC Review

Hi there, myself and my partner have a joint universal credit account. Last year we were asked to do a review, which basically meant we show them our last 4 months of bank statements which we did and then received separate phone calls to ask about any unusual bank payments or transfers which there wasn’t so everything carried on as usual. We went to the local job centre to do this for us as we are not very up to date with sending information like this via our phones and the man in the job centre said don’t worry if all ok you only have to do this every 4 years. Then a few months ago we were informed that we were owed a substantial amount of back pay dating back to 2017 when we first transferred over to universal credit. Then a few 2 weeks ago myself and my partner were asked to do another review asking for us to send the last 4 months of our bank statements. Do you know why they would ask us to do this agin because obviously we now have quite a bit of money in our account but it’s the back pay we were owed. Should we be worried in any way because it seems strange that if this is a random test why in 1 year should we have to do it twice. Your advice would be grateful. Thanks