GTP-C Error Indication is missing mandatory IEs
3GPP TS 29.060 7.3.7 indicates that there are two mandatory IEs in "GTP Error":
- TEI Data I (7.7.13)
- GSN Address (7.7.32)
OpenGGSN is sending neither of those, making it impossible for the peer GSN to identify for which of the PDP contexts the Error was sent.