Hi. Picture 1 shows the low poly mesh, everything looks fine and the left and right site are nearly identical.
Picture 2 shows the mesh being subdivided (using the number "3" button on keyboard). On the right site everything
looks nice and clean and on the left site the subdivision lines are totally messed up for no apparent reason. Picture 3
shows the mesh from the FRONT view and even though it's identical to the BACK site, everything looks fine.

So my question is, why is that small part of the model messed up and how can I prevent/fix it?

Picture 1:


Picture 2:


Picture 3: