Since July 1st we started receiving malformed IPN response from paypal with an odd string at the bottom of the IPN that is neither VERIFIED or INVALID but something like a non binary sign. This happens randomicly and both for payments related IPNs and for preapprovals.
If we try to resend the IPN from the paypal IPN history sometimes they get verified from paypal at the first time, sometime we have to retry more than once. Never happened before and nothing changed on our side in the ipn verification script that is old but work fine with the most part of the IPNs.
We've checked the endpoint and it is correct: https://www.paypal.com/cgi-bin/webscr
We've tried to resend some of those malformed IPNs and after one or more retry they comes out correctly VERIFIED.
When we try to get those affected IPN validated in the LIVE production, what we get is a bad request because of this odd string at the bottom of the affected IPNs instead of the VERIFIED or INVALID response:
‹ TŽK‚0„ïüŠ•»,M<Œ$¨ÄÔÇb›@‚ûÐøïmáäe’Ùùvgɦ¸æ¬mJ8±s Í=««â-bU²#bÁŠ5Ù')by‰iDzû)é%ÞØÁŽ’Ò2.à&_NKpGŒtJ|ÃæŽþQÞGd¦r:>Fj0r²ÀA¯ØžŒôÛçåF“²à&!µ±| é4`¨›ƒ,mþzø3ú ÿÿ Î[óâ