Dynamic Resolution Not Working Properly / At All

Since the latest patches, mostly since the expansion release, the dynamic resolution hasn't been working for me and for what I've searched around, it is happening to a lot of people (to some people it started during harbinger).
I have always played Path of Exile in Windowed Fullscreen since it is more convenient for me to alt-tab and do other stuff. During Fall of Oriath I used the same settings and the Dynamic Resolution was working wonderfully.
Now using Windowed Fullscreen does nothing to the game. I can go down to 10 fps and the resolution will stay the same. Changing to Fullscreen gets the Dynamic Resolution to work, but there seems to be a huge issue with it. As soon as I change to Fullscreen the resolution goes down to the minimum and my game looks awful (144p so to speak). As soon as I engage in combat it goes back to my resolution (1080p) and a few seconds after it will go back down to 144p.
So for the looks of it, the Dynamic Resolution is working in a inverse way or something. I don't know if this has been happening to anyone else and if someone has a way to fix it, but playing without Dynamic Resolution is extremely unsatisfying.

Picture of PoE on Windowed Fullscreen and Dynamic On:



Video of PoE on Fullscreen, going from 144p to 1080p and back to a lower resolution:

https://www.youtube.com/watch?v=8U8CE3ivpmc&feature=youtu.be