WordPress treating URLs with different categories as identical

Hello,

I’m having an issue where WordPress treats urls with the same subject but different categories as being identical, and adds a “-2” to the url.

For example, if I have a post with the url:

http://www.domain.com/fruits/apple

And another one with http://www.domain.com/healthy-foods/apple

It treats the urls as being identical and adds a “-2” to the end of the second post.

I know it’s not an issue of there being old trashed posts with the same url or anything like that.

Is there any way I can fix this? thanks