I think edge may have wiped out the STM and DSP firmware before updating the USB Audio Device (XMOS). Which means that the XMOS cannot be updated until the STM and DSP have been restored.
Luckily, there is a solution. 
To fix this you will need to first update the CONTOL SURFACE (STM/DSP) Firmware.
- Connect the X1800 PRIME to your computer via USB 1.
- Power on the device while holding BACK + FX CUE + TAP.
- Choose OK to start the update.
- Next, follow the specific steps below for your OS.
Windows:
- On your computer go to: C:\Program Files (x86)\Denon DJ\X1800 Firmware Updater\STM32
- Double click the Denon DJ X1800 Firmware Updater2 application.
- This will run the Control Surface (DSP/STM) updater application.
- Follow the on screen instructions to start the update process.
- Once complete perform a factory reset.
- Next, run the full X1800 Firmware Updater application again to complete the USB Audio Interface (XMOS) update.
- Note: Once this completes you can skip the second portion of the update as you’ve already done this above.
Mac:
- On your computer go to: Applications folder and find Denon DJ X1800 Firmware Updater.app
- Right-click/control-click on the app and choose Show Package Contents
- Go to Contents/Applications and launch FirmwareUpdater2.app
- This will open the Control Surface (DSP/STM) update.
- Follow the on screen instructions to start the update process.
- Once complete perform a factory reset.
- Next, run the full X1800 Firmware Updater application again to complete the USB Audio Interface (XMOS) update.
- Note: Once this completes you can skip the second portion of the update as you’ve already done this above.
Hope this helps!