We will try to reproduce this issue and will analyze the problem.
In the meantime, for further analysis, could you please run dxdiag.exe on your primary machine, click "Save All Information" then attach the output file (dxdiag.txt) on your next reply.
Could you please also tell us your secondary machine info.
- spacedesk viewer type (Android/iOS/Windows/HTML5)
- network connection type (wired/wireless/USB tethering/WiFi direct)?
Looking forward to your feedback.