Missing tick in source payload

Hi CRM Community,

since about three days the Exchange Integration of one of our customers is not working properly anymore.
I'm getting the following errors:

2013-05-03/07:32:10.012/MESZ [SyncEngine thread] ERROR com.sage.scrm.syncengine.exchange.ews.sdata.sync.SyncTargetManagerBase.processFeed com.sage.scrm.syncengine.exchange.ews.sdata.error.SageSDataGenerationException: Missing tick in source payload.

2013-05-03/07:32:10.028/MESZ [SyncEngine thread] ERROR com.sage.scrm.syncengine.exchange.engine.SynchronisationThread.run com.sage.scrm.syncengine.core.engine.error.SageSyncEngineException: com.sage.scrm.syncengine.exchange.engine.model.error.SageSDataEndpointException: com.sage.scrm.syncengine.exchange.ews.sdata.error.SageSDataGenerationException: Missing tick in source payload.

Did anyone of you experience such an issue before and does know how to solve it?

Thanks in advance