Something has changed with Purchase Orders. Once its converted to an invoice, it just says closed. So if you search the P/o it doesn't now link to relevant bill?

Hello accounts236,

Thanks for your post and welcome to the QuickBooks Online Community. 

We are aware of the issue with the estimates and purchase orders no longer showing hyperlinks to the bill/invoice which they have been linked to. I have added your account to our product investigation for this so that you will be notified once this has been corrected and the hyperlink is showing on the non-posting transactions. 

While we do not have a workaround for this while this is in progress, you can view the bill/invoice to check which purchase orders/estimates have been linked. 

Thanks