Back in the good old days exact match meant exact match, phrase was phrase and broad was broad!
Slowly Google have been changing the meaning and allowing ads to show when a keyword isn’t exactly specified in your account. Why? Well they’ll say that it helps capture all the search traffic without the need to have hundreds of keywords, but in reality it’s a good business decision, if they can get your ad showing up more then they make more money.
So if you look in your Search Query Report you’ll now see ‘close variant’ keywords showing up when you have just phrase, exact or broad match modifier keywords specified.
Should you be concerned? Not really. If you’re keeping an eye on the search queries that are triggering ads, avoiding ever using broad match without the modifier and continuously adding negative keywords you’ll be just fine