Playing the attached uip presentation (generated with srbench) when the cubes reach end of single 2s animation and should all be at left, black cube jumps into right side for a single frame. Console shows:
—
Failed to find root of cubic bezier at time 2 with coeffs: a = 0 b = 0 c = 1.13243 d = -1.13244
—

Note: Adjusting #Layer_1_Item2 position.x animation a bit e.g. "0.867565" -> "0.9" fixes this, so seems like rounding bug.