It's possible there's another cat in the neighborhood leaving its mark, but try cleaning it with an enzyme made for cat urine. Vinegar does nothing to remove the odor cats can smell.

I would treat the area all around and under, the doormat then buy a new mat.

annz could be right. Have you actually seen your cat doing the business on the mat or deck?

Its always recommended to keep your cat indoors. Especially if you have that much property, cats make great snacks for hawks and other country critters. If shes not fixed and goes into heat, other male cats will mark your door also.

I’m interested to know this too and not one of you answered her question 😠

Seven years ago?

Irrelevant

So, glad you cleared that up. Thanks.