Hey Cuthred, really sorry to hear about this
I there any way you could provide us your save? You should be able to copy it to an USB key following this method:
Using a hard drive or storage device
If you prefer to use physical methods for your save transfers you can also use an external hard drive or USB storage device. Simply connect the device you want to use to the console and you will be met with a prompt to format it for use with the Xbox One. Once this is done, you should be able to use this device to back up your saves.
Head to the ‘Storage’ menu and you will now be able to select any data you wish to back up to access a drop-down menu. Select ‘Transfer’ and you should be able to move any data – be it saves, games, or settings to the external device. Now, connect this device to the other console you want to use while it is powered off. When you turn it on you should receive a prompt to bring in all your data from your external device.
We've been reported a few similar cases, but we need the most files possible to help devs finds out what is going on.
Again, we're truely sorry that you faced such an inconvenience and we'll work our best to fix as soon as possible!