Discourse 1.9 stable + iPhone SE
Trying to suspend a user and tapping on the date picker does nothing. I do not know if it goes off-screen or what, since there is nothing on the UI.
Overall this is a bad change and UX regression over the beautifully simple old UI where the moderator would simply enter the number of days. Multiple taps needed to get it done and a calendar style picker (which I dont see) is not a good UI for mobile. The web is mobile first and in many occasions a moderator needs to suspend a user quickly, using the device immediately available.