I am facing a typical issue on Wsus server in my 8yrs career.
Scenario is i have 3 pcs with windows 10.

1) I have installed windows 10 on 3 pcs with same bootable usb.
2) When i access WSUS server to see if they are reporting on WSUS server to get windows update. Sometimes It shows PC 1 & PC 3 Sometimes it shows PC 2 & PC 3.
3) Actually all my 3 pcs have to reported on WSUS Server . But sometime PC 1 reported on WSUS Server. Which actually replaced PC 2.
4) I have checked SIDs of those pcs all have same SIDs..
5) All 3 PCs have different IPs & Computer name.

Now my question is why all of them are not showing together.