Not reproduced with Inkscape 0.47
reproduced with Inkscape 0.48 r9654 and 0.48+devel r9841 on OS X 10.5.8
steps to reproduce:
1) open new drawing
2) draw line
3) open fill&stroke > stroke style
4) change stroke width (using scroll wheel or the spin buttons)
5) Ctrl+S
Not reproduced with Inkscape 0.47
reproduced with Inkscape 0.48 r9654 and 0.48+devel r9841 on OS X 10.5.8
steps to reproduce:
1) open new drawing
2) draw line
3) open fill&stroke > stroke style
4) change stroke width (using scroll wheel or the spin buttons)
5) Ctrl+S