Jobs are not being picked up when switching from one job server to another

Hello Community,

we have a strange behavior in our test environment, so I wanted to ask here in the round, what could be the cause for it

Initial situation:

we have 2 JobServers with One Identity Manager version 8.1.5 installed and configured
- JobServer A has among others the server functions SQL Execution Server and ADS Connector
- JobServer B has among others the server functions Standard Report Server and SAP Connector.

Since a few days we observe the following behavior:
Job chains, which should write a change towards SAP at the end, are not fetched by the One IM service.
The job chain has in the 1st step a SQL query (ComponentAssembly SQLComponent) --> runs therefore on JobServer A
In the 2nd step then the AdHocProjection (ComponentAssembly VI.Projector.JobComponent) towards SAP --> runs on JobServer B

Current workaroun
When we restart the OneIM service on JobServer A, the jobs are fetched - we couldn't see any clue in the logs so far.
What could this be?

Thanks for any clue