Just sharing my way of handling stock splits - you may see it differently.
When my Schwab downloads a transaction reflecting a stock split - it merely does an Add Shares. Since this is not how I want Quicken to handle it, I DELETE that downloaded transaction, and then manually enter the Quicken Stock Split transaction…. done.
Also - as per
@Tom Young One problem you might face around the time of the split is that downloaded quotes might not line up correctly with the date of the stock split. The download quote provider uses the split-adjusted quote for a few days before the actual split date. This seems to happen every time a stock split occurs, so correcting a few days of downloaded quotes might also be necessary.