I have the Omega Colosseo - it's really a big brush but I don't think you have a "glue bump" issue here - rather a very thick and dense bunch of synthetic hairs. When you push from the inside, there is no bump feel at all. When you push from the outside, the base (white part in the picture) will indeed feel hard, but somehow this is to be expected, I guess.
It's a good brush, not my personal favourite though, but has lots of backbone and it's nice and soft. I still prefer the PAA Atomic Rocket though (26mm).