I haven't been able to reproduce this, but the Network folder barely works on any of my machines to be able to try it. In Opus or Explorer, it almost never lists any computer except the one I am on.
If you can trigger it via another method (e.g. typing the UNC path directly), let me know and I'll try that, but so far I haven't found a way to reproduce the problem locally.
The network credentials dialog in Windows 10 has had some bugs in the recent past that caused programs (not just Opus) to crash after it was displayed. We added workarounds for those, and I think Microsoft also fixed the issue eventually, but there may be other bugs lurking in there which manifest in different ways. Make sure you have the latest Windows updates if you haven't already, in case it's something Microsoft have fixed.