Hi @ubishaneymac1 and welcome to the forums!
Sorry to hear about your issue with getting the last shard in the crossover scenario. What platform are you playing on? Did you see the shard being added to the inventory after the fight? Did you exprerience any bugs or crashes during or after the fight?
If it's not possible to reload the save from before the fight, please also try going back to the location to see if you can pick up the shard from the woman's corpse. It would also be helpful, if you could provide us with a screenshot or a link to a short video showing the issue. Make sure to show the location where the shard was supposed to be and your current inventory showing it missing!
If you have any further questions, or require further assistance, let us know!