D50 for sediment bed

When using sediment cores to create a sediment bed, I am finding that the D50 value interpolated onto the bed appears quite different from the D50 in the core. My question is whether the cohesive sediment is included for both cases (i.e. when calculating D50 for the core and the bed).

Thank you,

There was an issue with this that has been fixed in the most recent release of EE7.1 v 140109