Twice now I have entered vendor bills into quickbooks online. I click save, wait until the screen pop up invoice # 12345 saved completes, but the bill does not save?

I appreciate the information you've shared regarding the bill, @paul255. Let me share some news to have this investigated further.

We've received similar cases or reports about the issue. I recommend contacting our support so they can add you to the affected users list. I'll show you how:

1. Go to the Help icon and choose Search.
2. Click the Contact Us button and enter your concern.
3. Press Continue.

Note our operating hours so you can contact us at your convenience. For other ways to reach us, refer to this article: QuickBooks Online Support.

See this article to learn more about tracking bills and recording the settlements: Enter and manage bills and bill payments in QuickBooks Online.

If you're interested with auto-matching the transaction, refer to this guide: Automatically match QuickBooks Online product transactions.

Drop a reply anytime if you still have concerns regarding bills. I'm here to lend a hand. Keep safe.