Frame property in text style apparently ignored in 1.3 files (unless default values used)

Windows 7, GIT commit: 6dffde5

1) load attached score, created in 1.3

Result: no frames appear around rehearsal mark or staff text despite the fact that they were present in 1.3

Rehearsal marks appear with boxes if the scores uses the default rehearsal mark text style. The imported score uses a different frame width and margin, but at least it works. If you customize the frame width or margin, however, these values get imported as 0.00sp, so no frame appears.

Initial investigation suggests the problem is that in 1.3, the text style properties frameWidth and paddingWidth were used to record values in spatium units, but in 2.0, those tags are assumed to be in mm values, and the corresponding frameWidthS and paddingWidthS tags apparently must be set in order for the frame to appear.

I wonder if a mismatch between sp and mm in the interpretation of these parameters is also responsible for #23019: Rehearsal marks change formatting after edit / relayout?