The Funnel Visualization report only shows one session to each step in the funnel, so if a user sees the same step twice—either by navigating back to it from another step or refreshing the page/screen—the second session shows as an exit to that step's page/screen.
In the example, you would see one session to /step1, one session to /step2, and an exit from /step2 to /step1.
The Goal Flow report shows loopbacks. If a user loops back or refreshes a particular page/screen, you see two pageviews/screenviews. (You may need to increase the level of detail to see more connections.)
In the example, you would see a pageview from /step1 to /step2 and then a loopback to /step1.
