I've been working with editing hosted feature services lately and have found a couple of bugs (I've noticed them in both Firefox and Chrome; I haven't tried other browsers) that really make the process annoying.
1. When editing attributes of a feature that has a lot of fields (enough so you have to scroll through the popup to see them all), the popup automatically scrolls to the top of the list of attributes after you've entered data into a field and click or tab to another field. VERY annoying.
2. I'm not able to consistently reproduce this problem, but when in edit mode if I switch the basemap, sometimes I'm no longer able to click on another feature and edit it (or even get a popup). The only solution seems to be to refresh the browser and try again.
Sorry if there's a better place to submit bugs, but I wasn't able to find one.