Let me help you sort this out, @tfwilson.

There are several reasons why QuickBooks may not recognize a match:

• The transaction is older than 180 days.
• The dollar amount in QuickBooks is different than what cleared the bank.
• The transaction type is different in QuickBooks than at the bank. QuickBooks wants to match a check with a check and an expense with an ACH or debit/credit card swipe.
• The transaction was recorded in a different bank account.
• The transaction from the bank is a payment/ deposit of two or more open transactions in QuickBooks.

It's also possible that the downloaded paycheck transactions were already added to your bank register. 

I suggest putting the transaction back to the For Review tab so you'll be able to match it.

Here’s how:

1. Go to the Banking menu.
2. Select the Banking tab.
3. Pick the Reviewed tab.
4. Search for the added paychecks.
5. From the Action column, click Undo. 

Once done, view the transaction in the For Review tab. Then, match your downloaded paycheck. 

In addition, here's an article you can read to learn more about how you can categorize and match your downloaded transactions:  Download, Match, and Categorize your Bank Transactions in QuickBooks Online.

Please let me know how it goes in the comment section down below. I'd be always around ready to lend a helping hand.