Apparent bug: Bracketed TupletNumber affected by Slur

[Daniel Rosen]

The following code produces the attached output, with the TupletNumber way down 
inside the Slur even though there is no apparent reason for the avoid-slur 
property to matter at all-in other words, this code should produce the same 
output as if the \override were commented out. (The bug appears to manifest 
only when the Slur begins on the first note of the tuplet.)

Is this a bug? I can't seem to find anything like it in the bugs list archives.

\version "2.19.25"
\relative c'' {
  \tupletUp
  \override TupletNumber.avoid-slur = #'outside
  \tuplet 3/2 { b8( b b) }
}

DR

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