Don't know what I am doing wrong  

Don't know what I am doing wrong

Hi guys,
First of all I must say, that I searched the internet and also tried to get some help from reddit (/r/prusa) but no one could help.

I got my MK2S kit some days ago and everything went smoothly. I built it in a day and started printing. The Prusa Sign came out perfektly, so did the prusa bottle opener. Then I tried something else and that's where the failing began. I tried to print a miniature for D&D which failed (nozzle partially clogged). I did several tests (which strangely had several layers mid print completely underextruded) and then decided to do a cold pull.

Did another test print which was fine and then tried to print the same mini with the excact same settings as the test print I just did - guess what happened.

I honestly don't know what I am doing wrong here. I use Slic3erPE all the settings are standard. Filament is completely new (opened 5 days ago) and not a cheap brand. Does anyone have any clue on what's going on here?