Trying to insert a table view cell at the top, without offsetting the current scroll position and causing a jump. Insert occurs when you tap one of the star accessory views, and seems due to the two different types of cells used in the table.

table-insert.swift

import UIKit

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
    let tableView = UITableView(frame: CGRect.zero, style: .plain)

    var totalAdded = 0
    
    override func viewDidLoad() {
        super.viewDidLoad()
     
        tableView.translatesAutoresizingMaskIntoConstraints = false
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
        tableView.register(SubtitleTableViewCell.self, forCellReuseIdentifier: "SubtitleCell")
        
        tableView.dataSource = self
        tableView.delegate = self
        
        view.addSubview(tableView)
        
        view.addConstraint(NSLayoutConstraint(item: tableView, attribute: .top, relatedBy: .equal, toItem: view, attribute: .top, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: tableView, attribute: .bottom, relatedBy: .equal, toItem: view, attribute: .bottom, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: tableView, attribute: .left, relatedBy: .equal, toItem: view, attribute: .left, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: tableView, attribute: .right, relatedBy: .equal, toItem: view, attribute: .right, multiplier: 1.0, constant: 0.0))
    }
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return UILocalizedIndexedCollation.current().sectionTitles.count + 2
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if section == 0 {
            return 3
        } else if section == 1 {
            return totalAdded
        } else {
            return 8
        }
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        if indexPath.section == 0 {
            let cell = tableView.dequeueReusableCell(withIdentifier: "SubtitleCell", for: indexPath)
            cell.textLabel?.text = "Grapes \(indexPath.row)"
            cell.detailTextLabel?.text = "I love grapes!"
            return cell
        } else {
            let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
            cell.textLabel?.text = "Oranges \(indexPath.row)"
            cell.accessoryView = createStarAccessoryButton()
            return cell
        }
    }
    
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        if indexPath.section == 0 {
            return 60.0
        } else {
            return 44.0
        }
    }
    
    func sectionIndexTitles(for tableView: UITableView) -> [String]? {
        return ["!", "*"] + UILocalizedIndexedCollation.current().sectionTitles
    }
    
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        if section == 0 {
            return "Cool Stuff"
        } else if section == 1 {
            return "Favorites"
        } else {
            return UILocalizedIndexedCollation.current().sectionTitles[section - 2]
        }
    }
    
    func createStarAccessoryButton() -> UIButton {
        let button = UIButton(type: .system)
        button.tintColor = .lightGray
        button.setImage(UIImage(systemName: "star.fill")!, for: .normal)
        button.sizeToFit()
        button.addTarget(self, action: #selector(starButtonTapped(sender:)), for: .touchUpInside)
        return button
    }
    
    @objc func starButtonTapped(sender: UIButton) {
        let buttonPosition = sender.convert(CGPoint.zero, to: tableView)
        guard let indexPath = tableView.indexPathForRow(at: buttonPosition) else { return }
        let height = tableView.cellForRow(at: indexPath)!.bounds.height
        
        print("Height: \(height)")
        
        let oldContentOffset = tableView.contentOffset.y
        
        totalAdded += 1
        
        tableView.performBatchUpdates {
            self.tableView.insertRows(at: [IndexPath(row: 0, section: 1)], with: .none)
        } completion: { (didComplete) in
            self.tableView.setNeedsLayout()
            self.tableView.layoutIfNeeded()
            self.tableView.contentOffset.y = oldContentOffset + height
        }
    }
}

class SubtitleTableViewCell: UITableViewCell {
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: .subtitle, reuseIdentifier: reuseIdentifier)
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}

Even weirder, it only occurs on the first insert, all the subsequent inserts don’t cause jumps!

@christianselig This one won't jump and will maintain contentOffset which is an old trick I used to do and it is ridiculously ugly but might be doing the job for you.

Replace the whole performBatchUpdates with this.

UIView.setAnimationsEnabled(false)
tableView.beginUpdates()

tableView.insertRows(at: [IndexPath(row: 0, section: 1)], with: .automatic)

tableView.endUpdates()
UIView.setAnimationsEnabled(true)

var contentOffset = self.tableView.contentOffset
contentOffset.y = oldContentOffset + height

tableView.setContentOffset(contentOffset, animated: false)

@TheCoordinator Ooo, thank you, I always appreciate more tools in the ol' belt!