N-step workflow issues: impossible to rolling back to the previous step

I had a page with 3-step work flow. I notice these issues on this type of workflow considering endUsreGuide document as reference for correct behaviors:
problem 1:
1) Steven (Author) pushed the WF to the second step
2) John (in charge of step 2) have only the possibility to pushed it to 3ed step but not rolling back to the author (screenshot 1)

problem 2:
3)John pushed the WF to the next step
4) Bob (in charge of step 3) has the same problem, he does not have the options rolling back to Steven neither to John. (screenshot 2)

problem 3:
5) Bob published the page.
6) Now I have this green icon with red line in the corner (I don't understand what does it mean, I don't find its explication in ENdUserGuide ) but in live mode I have don't have this page...(screenshot 3 )