It was the case that pre-moves could be canceled by clicking elsewhere on the board in mobile, this appears not to be working anymore for me. Now, clicking on the board does not have any effect and I am unable to cancel a pre-move at all. The bug appears to be the same on my computer as well.
The option for the board click is only for the app, in case you are trying on the browser. For the browser, on a computer, right-click cancels premoves. On mobile web, the only option is to refresh the page.
It was the case that pre-moves could be canceled by clicking elsewhere on the board in mobile, this appears not to be working anymore for me. Now, clicking on the board does not have any effect and I am unable to cancel a pre-move at all. The bug appears to be the same on my computer as well.