No deployment for healthy jobs

I recently encountered an issue, where I have few running and healthy jobs, but there is no deployments placed for them… What could be the reason for this?

jobs have update stanza, I found that the reasons for no deployments could be

  • job is not a service
  • is a service but has no update stanza
  • something about garbage collector which I have no clue what that is…

But for first two, I have either update or a service, but also some jobs that were not marked as a healthy had system type and now they are successfully deployed.

Also correct me if I’m wrong but is it true that job will have Helathy state info only if the deployment was succesfull?
What else could I check?