Strange typing artifacts (IDEA X 98.311 + Scala Plugin 0.4.207)

Using the above combination I'm getting some weird artifacts when I
type. I think that it's some kind of weird interaction between how fast
I type and the autocomplete functionality.

One of the more obvious examples is the keyword "def" which IDEA seems
to be messing up around 30-40% of the time. I typed a bunch of "def"s in
a row and here is an example of some of the things that I have been
getting (and yes, I am positive that I hit only 3 keys in every case).

   def f
   deff
   dfef