The monitor output meters both in Console and on the Apollo hardware (all Apollo models) are programmed to show clipping at -0.002 dBFS, i.e., right before clipping actually occurs.
This means that it's possible for the output meters to show clipping when no clipping or distortion is actually happening.
For example, if you're working in a DAW session and use a brick-wall limiter on your master output channel with a threshold / output setting of 0 dBFS, the output meters both in Console and on the Apollo hardware will show clipping even though no clipping or distortion is actually occurring. Clipping does not actually occur until the output signal reaches above 0 dBFS.