My guess:
== Symptom ==
Sometimes there job progress bar indicates a job is running, but actually it doesn't provide any "numeric" progress...
== Resolution ==
This behavior is by design.
== Cause ==
# There is a time window for every job to run in. (If a scan job is started manually, the default time window configured for the job is used).
# During this window, the server expects all computers on the network to report progress. If all computers are reporting their progress, you'll see a progress bar with a numeric value indicating that "at least one computer" is reporting correctly.
# If there is no update to progress from any computer in the last 30 seconds, the progress will be switched to a "rolling progress" bar.
# The job will finish only when all targets report "done"
== Possible causes for behavior ==
One of the possible scenarios to reproduce, using default config, with multiple computers connected:
# Connect only one of several computers to your server
# Start the quick scan job
# Observe the scan job to finish on the "connected" computer
# When finished, observe the progress bar in the console to switch to rolling -> the server is expecting more computers to report progress, but they're not connected to the console.
