I ran payroll, all paystub numbers are correct including Net Pay, banking updated, but when I go to "Match Transactions", why did QB's add more money to some of them?
Making sure your payroll information matches your bank transactions is a great way to make sure your books are correct. I can help you with getting your payroll matched to your bank feeds.
QuickBooks Online makes matching transactions easy by allowing you to download your bank feeds directly from your bank. I suggest logging into your bank account outside of QuickBooks Online and making sure the amounts match your payroll transactions. If they do match between the bank and QuickBooks Online account, you can download the .csv file and manually upload them by following these steps. When manually uploading transactions you'll see duplicates showing up from the original download but you can exclude them by following the steps here.
If the balances are off still it could be due to your browser health. This can be fixed by following this article on clearing the cache and cookies of the browser you're using. You can also try using a private browser such as Google Chromes incognito mode or a different browser all together.