It is stated here https://www.pmease.com/quickbuild/whats-new#parallel-workers that at child steps are getting picked up when free workers are available.

But it just executes the child steps in batches. Lets say we have 14 child steps in the parallel composite step and have set the max workers setting to 5 then the behavior is like this:

* Start first 5 child steps
* Execute them in parallel
* Wait until all of these 5 steps are finished
* Start second batch of 5 child steps
* Execute them in parallel
* Wait until all of these 5 steps are finished
* Start the last 4 steps
* Execute them
* Wait for finish

So not one step is waiting until it is picked up when there is a free worker. It gets picked up when all workers are free which potentially slows down the whole build if lets say all child steps are taking 5 minutes except one is taking 30 minutes.
So if the single long running step is in the first batch only one worker is used for 25 minutes and afterwards 5 workers are used again.

Please change the behavior that free workers directly pick up waiting task even when there are others still running.