Extruder is oozing some filament before it starts with a (few) layer(s)

[Luuk 0]

Hi, 
I have a problem with my Ultimaker 3. 
I have printed some prints. All printed with PLA and no support material. I had no problems at all.
Now I want to make a more complex structure, so I bought the Ultimaker PVA filament. 
I installed the filament and a BB 0.4 extruder. 
When I started a print: The print head goes to a corner and extrudes a little bit of PLA and then starts to print the first two layers and a brim. This goes without any problems. 
Then the print head goes to another corner of the bed and also extrudes some PVA. What I noticed when I saw this happening for the first time is that it takes +/- 30 seconds before some PVA comes out. But the real problem is that the little bit of PVA sticks to the nozzle instead of the bed and then the print gets pretty messed up. I tried to pause the printer and clean up the nozzle. That worked for a few layers. But after a few layers of PLA the printer again goes to the corner to put out some PVA. 

I have no problems with the concept of going to the corner and putting out some material. But how can I fix that the material that is extruded not ruins the whole print?