Unexpected IRT AR abort when receiving wrong PTCP Sync frame

The firmware might loss synchronization when an invalid sync frame is received. The problem occurs when "Sync with FollowUp" is used and the invalid sync frame is received between a "Sync Frame with Followup" and the "Followup" frame. The usecase "Sync with Followup" occurs in topologies with Profinet devices not supporting single step sync frame forwarding (e.g. ERTEC400 based Scalance switches).

It is expected that an invalid sync frame is ignored and does not affect the operation of the device.

This may happen in certification netload tests in case of active IRT communication while doing the netload test.