I hope that this is may be straightforward. Please read this FAQ:
You are using Asset and it appears that some commands being sent by Mosaic are not understood by Asset so it will not serve the file for track 1. Why it only happens with DSD64 .dsf files I have no idea.
That brings us to the reboot. Again there seems to be some kind of misinterpretation where a play command is being interpreted as Sleep. It cannot be Power Off as recovery from this requires a manual action. It is not possible via remote as, of course, being unpowered the Bartok cannot then recognise any commands.
I would suggest initially installing MinimServer2 for Windows and MinimWatch2 for Windows.
https://minimserver.com/install-windows-mserver.html
That will hopefully solve the Play issue. Will it affect the sleep/reboot problem? It is difficult to say as that would not at first sight appear to relate directly to the UPnP server. But it may, for some odd reason, be indirectly connected.