I have noticed this bug in several versions of Box for iOS app. When you have many files to share to a user in some app and you use a standard “Share in” iOS feature for that - everything works fine for several files. But starting from some file, it just stops working, Box app is getting unresponsive and the only way to keep sending files to that app from Box app to other app is to close and restart Box app. Note that it doesn’t matter where are you sending the files. It seems like Box app has some buffer / limitation for a number of files or total volumes of information to share during one “session”.