[trunk] wrong clef(s) when opening a score made with 0.9.6.2 (regression)

Setup: trunk rev. 3514, Windows XP w/ SP3, Qt SDK 2010.04 (Qt Creator 2.0.0, Qt lib 4.7.0)

Steps:
1) The attached score has been created under 0.9.6.2 with 2 instruments: a violin and a cello (names have been changed) with default treble and bass clefs respectively.
2) Open the attached score (created with 0.9.6.2) with trunk version.

Result:
A) the violin is displayed correctly but the cello is displayed in treble clef, instead of bass.
B) If a bass clef is dropped at the beginning of the cello part, the first line becomes correct, but notes in the second line remain as they were in treble clef: i.e. they become wrong being a 13th too low.

Expected result: the cello should be displayed in bass clef.

An image is also attached showing (part of) the same score in 0.9.6.2 and in trunk rev. 3514. (The image shows also other issues which will be detailed in other posts).

Thanks,

M.