Paypal now sends several variables as either
(I also have option_selection_1 vs option_selection_1_1 plus of course option_selection_2 vs option_selection_2_1)
s2member cannot cope with the newer format. that's the only difference I found and it seems with the newer format paypal choses to ignore the IPN.
Officially this is since July 13 - however I can trace back this format to July 07. Needs fix ASAP as s2member does not send s2member notification email, sets EOT to empty on renewals - and does not change user role on renewal (e.g. if account already subscriber - it's not updated to s2member_level1). Also any kind of invoicing tool therefore will fail if it depends on s2member fully processing the IPN first.
(It's not the only bug - I got some more s2member ignoring the IPN - but they are very rare - I will try to find out if I can find out why they are lost. However for those cases resending the IPN means that s2member will correctly work it down - while resending the new format IPN messages will fail no matter how often it's resent).
Other plugins have this problem too:
however It is really annoying that again noone reacts to my messages here (other thread) - anyone cares if paypal button payments go wayside? Also I'm not surprised that again it's me stumbling on a payment gateway bug...