My company gave me a laptop for work and I've noticed that it is using my company's DNS servers even when I'm at home and not on a VPN. I noticed this because I typed a search term in Firefox, which usually does a Google I'm feeling lucky search when there is no DNS result. I also see weird requests going out in Wireshark. I could provide more info if necessary. The IP settings are set to obtain a DNS server automatically. Where could it be picking up this setting?
It is possible your laptop is caching previous dns results. Depending upon which OS you have you might try other things, but in Windows
at a command prompt type: ipconfig /displaydns (LAN local connection status DETAILS will show you this also) to see where the dns records are coming from.
Possibly try: ipconfig /flushdns to force a new dns lookup when you are at home using that dns provider
Figuring out what is being used for dns resolution will get you closer to fixing it. Thus John T is right to ask what dns address is being used first.
If your network device TCP/IPv4 properties is is set to obtain DNS server address automatically, you can always add your companies preferred dns server but also include others such as google 126.96.36.199 & 188.8.131.52 or opendns 184.108.40.206 & 220.127.116.11
The network configuration allows a fixed DNS to be set. Check