No, even if you have a dedicated IPN configured for something else, E-junkie will not be affected by that. Our purchase buttons transmit our IPN requirements to PayPal with every checkout, which would override your manual IPN settings for any orders coming from our system.
If you still need to send IPN to a custom/third-party URL even for your E-junkie orders, our IPN-style Integration feature may satisfy that need for you.
The only time we require you to specify our IPN URL manually is when you are selling on a site like eBay where you can not use E-junkie purchase buttons to initiate the sale.
If you have have deliberately disabled IPNs manually in the past, you may see IPNs for your E-junkie transactions are Disabled in your PayPal account's My Account > History > IPN History. In this case, you may need to manually re-enable IPN in PayPal by going to My Account > Profile > Instant Payment Notification Preferences > Edit IPN Settings, where you should choose to Receive IPN Messages (Enabled) and enter this Notification URL: