“unable to complete” action – how to “submit to workflow” again

Hi

i have a simple “one step” workflow like mentioned on https://www.oasisworkflow.com/documentation/basic-concepts/commonly-used-workflows/one-step-workflow-details

everything works as expected when the reviewer sets the workflow action to “complete” and publishes the post

when the reviewer sets the workflow action to “unable to complete” and assigns the author again, the author gets the post in his inbox and can make changes

so far so good – but in this last step the author is not able to submit the post to the workflow again (the button is missing)
he is only able to save the post – but the reviewer will not be notified then, and the reviewer cannot “sign of” and complete the post

is there an error in my logic or am I missing something?

thank you