To add more, I think Kuma's fruit will play a heavy role in this. Since it can repel any inanimate object and also nerves and pain, wouldn't be surprised if Kuma remove his own memories and Vegapunk store the memories somewhere. Or Kuma removes his memories completely and Vegapunk is trying to recreate Kuma's memories but couldn't because he needs Kuma's DF ability for this. Plenty of opportunities.
See my post above mate ^^