Quote Originally Posted by Grist_To_The_Mill View Post
Considering that anti-missile systems involve firing missiles at the incoming missiles it’s possible that might cause one to go off course if not hit cleanly
Apparently a NATO plane tracked the misile. No information was given from where it was launched but Poland have asked for Article 4 to be activated.

Article 4

The Parties will consult together whenever, in the opinion of any of them, the territorial integrity, political independence or security of any of the Parties is threatened.