86.36 cm = 34 = long scale.
If you'll pardon my speculation ...
Any regular Alembic has 24 frets, this one has 22. IIRC, if you capo a 34 at the 2nd fret, you have roughly a 32 scale. The other way around, the 2nd last fret on a long scale is in the position of the 24th fret of a medium scale. So the medium scale fretboard is long enough for 22 frets on a long scale. The bass was refretted, perhaps even had a new fretboard fitted, and the ovals repositioned.