After domain transfer or renewal, the NL domain expiration date may be set to some incorrect value, not the same as on SIDN registrar side (sidn.nl).
Since September 16 sidn.nl changed their API behavior to include parameter to the call back to PBA-E. PBA-E usually uses such parameter to set correct expiration date of domain subscription.
"exDate" parameter is part of standard EPP XML protocol (http://tools.ietf.org/html/rfc5731) and it is used in different registrars, that is why it is supported by PBA-E.
Regarding .nl domains it has no actual meaning as they do not expire, while for other domain zones this tag returns expiration date of the domain.
The parameter returned by SIDN has some other value but domain expiration date, that is causing date discrepancy between PBA-E and SIDN.
The internal request with ID PBA-59222 was submitted to the Parallels Automation maintenance team so that PBA won't use any dates which may be returned by SIDN.