Strange phrasing slur with autoBeaming = ##f

[Stemby]

> I'm not top posting.

Here is a short example:

-----
\version "2.14.2"

% Strange phrasing slur with autoBeaming = ##f

\layout {
  \context {
    \Score
    autoBeaming = ##f  % try to comment this line
  }
}

\relative c'' {
  \time 3/4
  \key f \major
  r4 r8 c8 [ \( ( d8 ] ) c8
  a8 bes8 c4 \) r4
}
-----

Regards,
Carlo