Why would a user on a Domain joined PC (or any PC, really) have two entries in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList, in the case as these SIDs:
S-1-5-21-3229509536-3853329613-2519243864-1117
S-1-5-21-3840458582-4119228877-3303071312-1127
This machine has never been WORKGROUP, it was Domain joined by an admin account when deployed and the user added as a domain user. The user in question is admin on the PC.
There is a VirtualBox installation on this PC, where the user has a Windows 10 VM with same username but I can't see how or if that would affect the actual PCs registry.