Bridge edge loop acting weird between 2 clean edge loops How edges looks like before bridge edge loop: 

How mesh looks like after bridge edge loop: 

Why is it acting so weird, 8 edges in the first loop, 8 edges in the second loop, that seems simple to connect. Am I doing something wrong?
I think the vanilla "Bridge Edge loop" is not quite efficient.

I tried the "Bridge" tool from "Loop Tools" addon, it works like a charm:



This addon is shipped in Blender. Just enable it in the user preferences and you will find the Loop Tools submenu in the Specials menu (W by default).