The cartesian axis panel determines the amount by which its ticks' labels overflow on both ends (left and right, if axis is X). When the axis has a fixed or maximum size, the overflow calculation should consider that part of the overflow will be clipped.
This issue exists since the CCC layout started to determine axis ticks labels' overflow, and has surfaced in the forums:
The attached image shows what can happen when tick labels have a long text.
The following chart definition reproduces the problem: