OMG How Did I Get Duplicate Category?

Hope someone could answer this peculiar WP site structure I found on some sites. When looking at the url, one could see there are duplicate categories in there like below:

h**p://**w.domain.com/blog/category/general/

The word "General" is the category defined. However when looking at the posts within this category, you'd find the permalink structure completely different as below:

h**p://**w.domain.com/general/postname

Is there any way to keep the category permalink structure as:

h**p://**w.domain.com/general/

Would G bots be able to figure out your complete site structure or end up crawling and indexing two different types of category link?

NOTE: This would happen when WP setting is changed to use static pages.

some time it happen , we dont do this but by chance we met with each other.