Donut hole with XB-D

Hey there,

I modded a cheap AA flashlight with an XB-D in 3C tint. I had to remove a bit of the reflector bottom to get the led far enough into the reflector, but now the spot has a hole in the middle that is darker and seems yellower than the spot itself.

Is this to be expected with such an el-cheapo reflector, or could it be that I still have to remove more reflector material?

Thanks

Steve