Need some clarification on invoice date field in invoice workbench

Hi Guru's

Need some insight on below scenario:

Open AP Period: Aug-19

Open GL Period: Aug-19

Open Purchasing Period: Aug-19

GL date basis setup: System date

Now entering one invoice:

Invoice Date: 1-MAR-2019 (system is throwing a caution sqlap 10006 the invoice date you entered is not in an open accounting period)

GL date: 1Jul-2019

Now, when i click ok on caution for sqlap 10006. It allows me to create an invoice even the receiving is done in the month of April

As per my understanding it should have not allowed me to create back dated invoice as March -2019 period is closed.