iMac USB Problems

[EduRoamer]

We have a fleet of iMac 21.5" 2017 in use within our music department. We have a recurring issue of the last USB port on the back randomly stop working, and after a while it will come back, sometimes after a restart and sometimes it takes longer.

 

It is always the last port that has the issue. We suspect that the devices plugged in may be drawing too much power? All Macs have the following connected: Mouse, Keyboard, Scarlett Solo box, Music Keyboard (via MIDI to USB)

 

Has anyone had a similar issue and resolved this, or any way to diagnose further?

 

Thanks