Hi,
I noticed you said you are not associate a work or school account to that PC. So try to check if the issue disappear after associate AAD account (with Windows 10 E3/E5 or A3/A5 license assigned) and login it.
I noticed you said before: Please check if the user signs into this device using Active Directory account and MFA (multi-factor authentication) is enabled. All users are logging into AD, there is a mixture of MFA and no MFA
However, from capture, the first computer is hybrid AAD joined. From official article Multi-factor authentication says,
I would recommend to try resolved measure for Windows 10 1809.
As you have created a ticket for this issue, I recommend to contact with ticket owner if they have any resource for escalate. As we belongs to different system, forum engineer will not familiar with their phone support process and resource.
I will be appreciate if you could share your result if the issue was resolved in that ticket. It would be useful for other customers which encounter same issue with you.
Bests,