A funny thread between the 3h marker and the tip of a sort of secondary second hand is visible in IE 9 and IE 10. The same effect can be seen in IE 8 when using excanvas.js.

If the second hand is switched off, then this effect will affect the minute hand but only after it jumps to the next minute marker.

Another observation: when using a custom skin that does not have an outer border and no minute/hour markers, this effect is not visible.

The effect is visible with coolclock 2.1.4 and 3.0.0-pre.