You are seeing a vat report for a period already filed and somehow either by an adjustment or re dating or a new transactions dated in that period have turned up.
QB will have accounted for this in the next period or current period depending on when the adjustment was made.
To see this look at the vat exception report for following vat periods or current period and you will see it is accounted for you do not have to do nothing. Its all correct
Double click box 4 figure or the option that says how is this figure calculated to see what the transactions are and open them to see when changes took place then look at the vat exception report for that period.
If you really want to make that report zero you have to find the changes that caused it and change the dates to correct. but its not necessary as every thing will have been filed correctly.
This is what the vat exception report is for it reports out of period postings that are posted in current period.