Troubleshooting Help - 50+min delay between paypal payment + order appearing in admin

New issue, noticed this evening - no issues earlier today.
I'm getting a long delay between payment posting via paypal and the actual order confirmation email going out and the order appearing in the admin. The order itself also does not appear in the customer history during this time (to be expected, I think). Email archiving is turned on, and it also does not have any records to enlighten me.

In once case, I received he paypal payment confirmation and then just under 50 minutes later, I received the order confirmation. In another case, I'm closing on 50 minutes ago having received the paypal payment confirmation, but still have not yet received an order confirmation from the cart.

I've confirmed that email handling is working correctly (as I have vague recollection of this causing problems previously). I am unaware of any changes made on my servers at my host - but I'm still looking into it - they've surprised me before :(

Zencart v 1.3.0.2
security updates installed, but no changes made recently.
PHP v 4.4.9

Thanks in advance for any guidance or insight you might provide.
-Stephanie

The PayPal IPN module is completely dependent on PayPal's servers notifying your server of the transaction. If PayPal's servers are backlogged, then your store will NOT see the order until PayPal's servers catch up.

Your options:
a) live with it -- that's a limitation of choosing to use the Website Payments Standard (aka IPN) method for payment handling
b) upgrade to at least v1.3.8a and use the much more stable PayPal Express Checkout option instead

Thanks Dr. Byte! I appreciate your insight and swift response! I suppose I should consider myself lucky that I have not seen this issue before.
-Stephanie