I have a fairly complex setup using two iCM4+'s connected to a Windows 10 PC running Ableton Live. Both iCMs have all their DIN ports hooked up, and have their USB host port connected to a powered hub (7 ports) each with 7 devices hooked up. All the devices connected to the USB hubs have reserved USB host ports.
I have recorded a loop in Live that plays a combination of synths and after a while of playing the loop, the instruments hooked to the USB host port of the first iCM seem to stop receiving MIDI. The DIN ports are still active but the USB host ports no longer send MIDI (at least on one of the iCM4+'s). I have tested it with two different USB hubs - a cheap one and a brand name (Belkin) one. I have to reset the iCM4+ in order to get the USB host connection back.
The devices connected to the USB host are: DSI Prophet 6, Roland JD-XA, Waldorf Streichfett, Korg KP3, Korg Kaossilator Pro, Novation Bass Station II, Medeli eDrum. The track itself uses the P6, JD-XA and Streichfett