An address belongs to a connection, not a permanent identity
Two websites can report different public IP addresses for the same computer. That does not automatically make either result wrong. A service normally observes the outward-facing address used for its connection. A device can use several connections or address families, sometimes through an intermediary, so there need not be one address that describes every request it makes.
First check whether the addresses themselves differ. Different country or city labels are a separate question, even when they appear next to an IP address.
A proxy or VPN may handle only some traffic
Split tunneling can send selected destinations through a VPN while other connections use the ordinary access network. Proxies may also apply only to certain websites or applications. One service might therefore see the broadband connection's exit, while another sees an intermediary's exit. A domestic site and an overseas site are one possible example, not a rule about where traffic must go.
Applications can have different proxy settings. A browser's result does not describe every other app, and a connected VPN icon does not establish the scope of its coverage. Also, a different forwarding route by itself does not necessarily change the source address; address translation, intermediaries or a change in the actual connection matter.
IPv4 and IPv6 can both be in use
A network can provide both IPv4 and IPv6. One destination may accept only IPv4 while another supports IPv6. Where both are available, software can choose between them according to connectivity and connection behavior. The resulting addresses can look completely different without any change of device.
A VPN or proxy may also treat the two families differently. Seeing an IPv4 address alongside an IPv6 address is not sufficient evidence of a leak or an attack. Assessing a privacy setting requires checking which apps, protocols and traffic it is intended to cover.
Timing and network changes affect comparisons
Switching between Wi-Fi and mobile data, changing access connections or receiving a new address can alter the visible exit. An older tab may still display its previous result while a newer one reflects the current connection. Compare fresh observations at roughly the same time, after confirming the active network.
Restarting a router does not guarantee a new dynamic address. Conversely, a shared public address may serve several users. Each observation describes a particular connection at a particular time, rather than every connection on the device.
The same IP can have different location labels
If the address matches but its country, city or organization label differs, consider database updates and differences in what the fields describe. IP geolocation is an estimate about network addresses, not a GPS reading of the device. With an intermediary, it may describe the exit rather than the user.
Check the full address, address family, observation time and connection settings before comparing location labels. These checks help explain a difference; they do not prove that one service is always right or that a VPN has failed. Understanding which connection was observed is more useful than assuming there is one IP for every situation.
DNS paths and website exits are separate
A resolver handles the name query, while the web connection reaches the returned destination. These can take different paths. A resolver’s country differing from the country of a website-visible IP does not by itself prove a DNS leak; the expected VPN or proxy policy matters. Read What is DNS, and how does a domain find an IP address? for the underlying distinction.