Messages are getting stuck in queues. Restarting the K2 Service does process the messages, however with a lot of messages being stuck the service would have to be restarted the same amount of times as the amount of stucked messages that there are.
Messages are getting stuck in queues.
This is a known issue where the workflow scheduled starts: SourceCode.EventBus.Scheduler.ProcessStarter.ProcessStarter
An existing bug is known - where the sync flag on management studio is the wrong way around, so the Async tickbox on Management page on the schedule needs to be unticked.
*Please change the async check so that the process will start async : synchronous:false,
You can confirm with the debugs (the debugs can be obtained via a support ticket) in the K2HostServer_EventBusServer_ logs that the AssemblyTypeName: SourceCode.EventBus.Scheduler.ProcessStarter.ProcessStarter has synchronous:True, this should be synchronous:False
If synchronous:True, then MSMQ will start the process, and wait for a client event or process to finish before returning to process the next MSMQ entry.
* You would also need to provide your KUID