Help with inverted cone print

[eestelles]

Hello,

I have a Dremel 3D45 and I managed to print successfully many times in Dremel Nylon an inverted cone (even without raft). However now I'm testing other type of Nylon (Fiberlogy Nylon PA12) and I'm having a repetitive issue at the beginning of the print. No idea what you call this:

The interesting bit, is that the other side of the cone is smooth and fine:

Any idea what is this or why is happening?
When I print the full piece, is fine, except for that lumpy bit at the beginning.