We apologize for the instability of composr.app and appreciate your patience. We are working on the statistics addon and trying to find an optimal way to store and render data. Unfortunately, we have yet to find a solution that can handle the traffic (and therefore, tens of millions of statistical records) of composr.app. We're working hard on one.
#5301 - CKEditor: Cursor placement issue when adding a block
Easy workaround: Right-click the misplaced yellow box in CKEditor, click copy, delete the box, place cursor where you want the box, and paste.