Purchase Invoice Link Field is disabled after the parent document is submitted

Hi All,

Please find the erpnext and version details below:
erpnext 13.0.0-beta.14
frappe 13.0.0-beta.12

The link field for Purchase Invoice is not working when linked to other standard doctype like Payment Entry or any custom doctype. The link is enabled until the doc is in draft status, but once the document is submitted, the Purchase Invoice link field behaves as a data field and does’t show the link to Purchase Invoice. Have logged in as administrator user, so should not have permission issue. Please find the below screenshots for reference.

The link for other doctypes works fine:

Is there any way by which we can resolve this, or any suggestion for what I can check on this? Or is there any setting which is not allowing the document from being linked??