Using groups-paypal-1.3.1 and groups-subscriptions-2.5.0
[groups_paypal_return] is empty when doing a real (recurring) subscription. But it renders fine when doing a one-off payment.
I don’t know if it has something to do with the time that elapsed before IPNs were generated.
At least today, in various tests I did, IPNs of type subscr_signup and subscr_payment occurred between 5 and 54 minutes after checkout was made.
Even though [groups_paypal_return] shows nothing, subscription gets active status after IPNs arrive.
I have only worked in sanbox so far.
I didn’t use show_message shortcode attribute (if that’s what it is for).