How to properly duration for Autoscalling to 0?

[stefangluszek]

With autoscaling to 0 I've noticed that it's possible to end up with a workflow job queued that never gets scheduled. Let's say I have the duration set to 1m but the workflow job takes 10m.

1. workflow job (A) is queued
2. number of desired replicas is set to 1
3. wait for 5 minutes
4. queue another workflow (B), the scale up trigger duration expired so no new replica will be created
5. workflow job A finishes which reduces the number of desired replicas to 0
6. workflow job B never gets a runner

Is there a way to work around this or do I just have to set the duration to the longest workflow + queue time, which might be unknown?
Why is the duration required at all if we scale down when workflow jobs are finished?