Well it's pretty simple ....HE LIED ! He lied because advancing troops acroos the border , whatever the prick said , is still by definition an invasion !
And he kept lieing before that saying over and over he wasn't going to .
You don't seek water in a desert and you don't look for truth in Putins pronouncements . His career has been a litany of lies -- learnt in the KGB ! Spies need to lie well !