Is it really that unusual?Not unusual but it depends on the implementation. Usually this is done to prevent credential stealing/sharing. There should be logic that measures time from logging in from one location to another. e.g. If you logged in from NYC and then tried to log in from Istanbul 30 minutes later then based on the limitations of transportation logistics it should be logical to block that attempt.
Another use case for geological based checks would be checking the box to attempt to block countries that are legally sanctioned. And then there is the topic of VPN's and what to do about them.
This is just my opinion but I would open a case and ask for more details from them as to what happened and why.
