Calligraphic Lines wobble when tablet pen's Y_tilt is forward

Hi. I found that the Calligraphic lines sometimes moves abnormally.
Some of them accidentally wobble, cease or enlarge.
I experimented and realize that this occurs when the Y-axis-tilt is forward(=when its value is minus) and perhaps when the parameter "Fixation" is other than "0".
This is more likely to occur when the line is curving, in other words when the tilt is drastically changing.

I'd like other users to confirm.
I'm afraid this might be just dependent on my environment.
I use inkscape on Ubuntu Linux gutsy 7.10, linuxwacom-0.7.7, subversion "Inkscape 0.45+devel, built Mar 15 2008".
My tablet is Intuos 3, PTZ-630.
I ran "xiwacom"(wacom tablet dump tool) and made sure that the tilt sensor was able to get value.

Here is an attachment of the typical example of "wobbling" line.