I have this problem at work when trying to have a device maintain connection to a HP Printer (Laserjet Pro M477fnw) via Wi-Fi Direct. Because it is also connected to the internet via Ethernet, the Wifi-Direct hotspot in the printer always stays inactive every time after reboots. It's as if Windows 10 thinks one connection is enough, even when I checked "Connect Automatically" for Direct-ea-HP-m477....
It turns out this can be fixed in the registry:
HKLM\Software\Policies\Microsoft\Windows\WcmSvc\
See if the GroupPolicy subkey exists, if not with WcmSvc highlighted, right click on WcmSvc and Choose New -> Key and name it GroupPolicy, then click GroupPolicy and then in the right pane, (right-click) and choose New -> DWORD (32-bit) and create value, name it as fMinimizeConnections and Click OK. Now, reboot and test. This policy allows you to connect automatically to wireless network, even with a LAN plugged in and works on both Windows 8/8.1 and 10.
Now the user can both print and scan via Wi-Fi Direct without any manual connection/setup. Other users should be able to do the same too. According to the manual, Wifi Direct allows up to 5 device connections.