Some subscriptions that had expiration date after 28th were renewed till 28th in February. For example expiration date of the subscription in January was January, 30, but when subscription was renewed in February expiration became March, 28.
Only subscription with 'Auto-Renew' option enabled are affected.
The issue is caused by bug #PBA-42719 which is fixed in PBA-E 5.5.
You can find all affected subscription using the following query:
select * from (SELECT "subscriptionID", "startDate"::abstime, "ExpirationDate"::abstime, "Status" as Status, "IsAutoRenew" as AutoRen, EXTRACT(DAY FROM to_timestamp("startDate") ) as startD, EXTRACT(DAY FROM to_timestamp("ExpirationDate") ) as expD from "Subscription" ) A where startD in (29,30,31) and expD = 28 and AutoRen=1 and Status=30;
Then you can correct expiration date using start date of the subscriptions. For example you can do it in Provider's control panel using 'Change Expiration Date' button on General tab of the subscription.