My program is a test of a rigid body simulation package, pyode. The
scene consists of a few boxes near position (0,0,0) and a sphere.
The sphere starts from a position behind the viewer, rolls towards
the boxes, crashes into them, bounces back towards the viewer,
then continues to roll far behind the viewer. After the sphere rolls
for a little while, the near clipping plane begins to move forward into
the scene. I have "autocenter" turned off, and the forward
progression of the near clipping plane seems to be related to the
distance of the sphere from the scene.
I have experienced these problems with versions 2.1.9 and version
2.9.7. I am using Linux.