UITableView dynamic cell heights only correct after some scrolling

This worked for me when other similar solutions did not:

override func didMoveToSuperview() {
    super.didMoveToSuperview()
    layoutIfNeeded()
}

This seems like an actual bug since I am very familiar with AutoLayout and how to use UITableViewAutomaticDimension, however I still occasionally come across this issue. I'm glad I finally found something that works as a workaround.

I don't know this is clearly documented or not, but adding [cell layoutIfNeeded] before returning cell solves your problem.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    TableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"TestCell"];
    NSUInteger n1 = firstLabelWordCount[indexPath.row];
    NSUInteger n2 = secondLabelWordCount[indexPath.row];
    [cell setNumberOfWordsForFirstLabel:n1 secondLabel:n2];

    [cell layoutIfNeeded]; // <- added

    return cell;
}