I'd say it's pretty normal for a workflow. If you have a lot of things that can proceed independently of each other, you're likely to see that characterized as "multiple workflows".

Say you're making a four-course meal. In the abstract, each course is independent of the other three, but internally the steps of its preparation have exactly this kind of dependence, where step 3 is scheduled after step 2 because doing those steps in the other order will ruin the food.

If you ever want to make just one of those courses -- maybe you're going to a potluck -- now you've got an almost fully sequential workflow.

(And in practice, the full four-course meal is much more sequential than it appears in the abstract, because many of the steps of each course must contend for scarce resources, such as the stove, with steps of other courses.)