Ah Spece2goin, thx for answering. So I don't feel all alone here.

A texture-streaming problem? I guess it's more related to the new
added halo effect during transition, because it was a lot smoother
before v1.30. It isn't optimized just yet. Simple as that.

There are times were everything comes together in a very bad way like
the shuttering of the transition effect and the '1 / awesome' tearing right
over the middle of the whole screen. Just zone Moa Therma or Metropia
and watch framerate drops and tearing in action at the turn before the
start/finish line, respectively. In non-ZONE mode this isn't much of a
problem, the game even switches to a lower resolution if necessary.
However, in ZONE every frame counts.