I'm running OpenSUSE Leap 42.1. According to about dolphin dialogue, the version of Dolphin is 15.08.3. KDE Frameworks 5.16.0- Qt 5.5.0. and the Xcb windowing system.
When I access a webdav folder on box.com, after I select the file, Dolphin properly asks me what program I'd like to run. As soon as I select it, the program will open and everything works normally. However, that instance of Dolphin immediately becomes unresponsive. Attempting to do anything in the window, gives no response. If I press the X in the window corner to close it, I'm told that it's not responding and prompts me to terminate it (which works). No damage is done at all. However, I have to start a new instance of Dolphin again to use it. It normally doesn't crash, so I don't have a core dump to submit. It is reproducible every time.
Thanks for the bug report. This is a bug in the KIO framework which has been fixed recently. Please upgrade to KIO 5.17.
*** This bug has been marked as a duplicate of bug 353037 ***
Thanks for the good news. Appreciate the quick follow up.