Windows 10 laptop with an elephant's memory for internal-only DNS server

I have a remote user who reported chronic connectivity problems with her new Windows 10 laptop. I had her do the netsh winsock reset catalog and netsh int ip reset reset.log commands to resolve her problems, which worked, but the next day they came back. Her current procedure is to start the computer, have no Internet access, run the commands, reboot, and have Internet access until the next day.

Recently we bumped into each other at a training event and she was able to let me look at the computer in its non-working configuration. What I identified was that name resolution was failing and when I did an NSLOOKUP, much to my surprise our internal DNS server address was listed instead of the hotel's DNS server. Her connection is DHCP-only and gets the internal DNS server when she makes a VPN connection.

We were able to repeat the NSLOOKUP test once she returned home and saw the same thing: the inaccessible internal DNS server listed instead of her ISP's DNS server. We have a number of other employees with the same setup but none of them have reported this problem and I haven't been able to find much online about it.

Does anybody have a suggestion on what we can do to keep the computer from remembering this temporary DNS setting forever?