change collection view cell background colour dynamically on button action not working

I try to change the background colour of specific cell on button action. Color of cell is changing but but I scrolling this collection view the color of cell misplace from there original position

when I scrolling this collection view which contain question number, color position in this control misplaced like in this image

How I can handle this problem that collection view cell color never change their position automatically.

This is my code on button click to change the color :

let indexs = IndexPath(row: currentQuestion, section: 0)
let celi = questionNumberCollection.cellForItem(at: indexs)
celi?.backgroundColor = .blue

Problems is

You are changing the background color of the cell but you're not maintaining the state of the cell anywhere in your model which is important in the case where the cell is reused while scrolling.

Solution:

A simple and standard solution might be maintaining a state variable in a model or as a separate array, and change the background color in the cellforRowatIndexPath method.

Example:

struct Question {

    var desc:String
    var mark:Int
    var status:AnsweringStatus
}

enum AnsweringStatus {
    case notAttented,correct,inCorrect
}

class ViewController:UIViewController,UICollectionViewDataSource {

    var dataSource:[Question]!


    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return dataSource.count
    }


    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ShowCell", for: indexPath) as! ShowCell
        switch dataSource[indexPath.row].status {

        case .notAttented:
            cell.backgroundColor = .gray
        case .correct:
             cell.backgroundColor = .red
        case .inCorrect:
             cell.backgroundColor = .green
        }
        return cell
    }

}

Have showcased only the parts necessary to solve the issue. So on click of the button just changing the state in the respective model object using the index path and reloading the collection view will do the job.

Provide more insights about the issue, if this doesn't work for you.