What is this from a 400W venture MH lamp?

[voovoov]

I am upgrading my projector from 250W lamp to 400W lamp. I bought a lamp and ballast from hidirect.com basing on the information from lumenlab. It appears that the ballast is better in quality than the one I bought from 1000bulbs, however, I found a spot in the lighting as shown in the attached image. Can anybody kindly tell me what is going on with my lamp? I know it is impossible to use this lamp as a light source, is this a problem with the same model or unique case.
The lamp is venture 40124 (MS 400W/H75/ED28/PS) link:http://www.venturelighting.com/LampsHTMLDocuments/Uni-Form_400W_lamps.html#400W
the ballast is venture V90D7612 link:http://www.venturelighting.com/VLPS/Opti-Wave400W.html

 

[cbm5]

Looks like the arc isn't in the same place as the old lamp? Or maybe the arc is bigger and most of the light is outside the point where the projector optics focus?

 

[WMT]

This can be done from wrong reflector position.Are you using one?
Is it placed properly?The other thing that comes in my mind is a light leak.If it is nothing of the above then it is very strange!
Looks like your lcd leaks light due to bad polarizing flters!When you upgrade to 400w did you also upgrade your cooling system?