I have implemented an approval workflow in a controlled document library. The workflow is triggered when a new document is uploaded or an existing one is modified. There are about 3 approval steps before the document gets published. The way I have configured the approvals is by flexi tasks, with a link to the document. The workflow works properly, however I am facing an issue with version control. 

As the document moves through approvers, the minor version changes; i.e. from 0.1 to 0.2 e.t.c; even when the approver does not make any changes to the document. I don't want the version to change unless an assignee checks out the document and checks it back in after making changes. 

I suspect the version change is caused by the fact that there's a field that the workflow updates after every approval. Is there a way to avoid version change when a field value changes?