DNS translates a domain name "example.com" to an ip address pointing to the server. It tells your browser how to reach the server. It is unlikely the reason.

the common way to detect your location is by checking your ip address. Usually there is a database (i.e. maxmind) that keeps a record of which ip address subnet belongs to which location.

you can do a check with a reverse ip geolocation lookup tool to verify this.

so either:

• the company haven't updated their database yet
• your IP range was recently bought or rotated by your isp