Ubuntu only using one DisplayLink; 2 detected

[jamesreinders]

I have attached the output of DLSupportTool

I loved one DisplayLink so much, I bought and added another after I had my system working with one DisplayLink. But - ONLY one works at a time on Ubuntu - even though both are clearly detected. Why?

I have tried uninstalling and reinstalling the DisplayLink software. Everything is up-to-date and upgraded. I have tried many things - nothing changes. I have, of course, rebooted many many times during this process.

THE PROBLEM:

Ubuntu (X11) is only using ONE of the DisplayLinks (which ever is plugged in first).
Both DisplayLinks appear to work, and switching which USB they are plugged into does not matter - they work from either USB port that I try, but only one at a time.

ls /dev/displaylink/by-id
usb-002-003-DisplayLink_Displaylink_USB3.0_Display_PCT13600000 014
usb-002-005-DisplayLink_Displaylink_USB3.0_Display_PCT13600000 014

xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x7b cap: 0x9, Source Output, Sink Offload crtcs: 2 outputs: 7 associated providers: 1 name:modesetting
Provider 1: id: 0x41 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting

This is a laptop, with a VGA monitor connected, the lid closed. The DisplayLink USB devices seem to both work - but only one at a time.

How can I get X11 to see/use both of them???

I have attached the output of DLSupportTool