Why are there missing purchase orders on the expenses vendors transaction list?

Hello there, Rultract. I'm here to ensure you'll get your purchase orders.

Filtering Dates and Types can lead to purchase orders not appearing in the list of related transactions when trying to match them with bills. Double-checking your filters can help ensure all relevant transactions are visible for matching. Kindly follow the steps below:

1. Go to Expenses.
2. Select  Vendors and click on the vendor of your choice.
3. Hit the Filter dropdown arrow to edit.
4.  Set the Type to Purchase order.
5.  Set the Date to All dates.
6. Click Apply when done.

I've added a screenshot below for visual reference.

Alternatively, you can generate reports in QuickBooks Online(QBO) to help you view purchase orders. 

To run a purchase order report:

1. Go to Reports (Take me there).
2. Search for and run an Open Purchase Order List report, Open Purchase Order Detail report, Purchases by Product/Service Detail report, or a Purchases by Vendor Detail report.

Finally, learn what the audit log in QBO can do and to keep track of your activities. You can view who modified your books if your account has multiple users.

Let me know in the comments if you have more questions about purchase orders in QBO. I'd be happy to assist you further.