This is an issue with my Vivofit 2 and the iOS app.
I have had the problem for a few days now, though I am not sure when it first appeared. I suspect a change I made to see the number of steps during activity started this, but I can't really be sure. Before that I had the issue of no date screen toggle for normal operation, and that got fixed, so an app update might be causing my current issue as well.
For screens visible during activity I used to have HR, activity time and activity calories. Possibly after setting those + activity steps, activity screens started getting completely wild. I cannot seems to be able to set HR and calories to show, for example - I can toggle the settings in the app, but after a sync, there is only one or the other (and the toggles in the app have moved to display whatever the screens show). In addition, a few times I even got time and date to show. While I might have confused time with activity time during the testing, date seems extremely unlikely.
Using the latest app version and Vivofit 2 3.50.0.0 firmware.