In some cases you may think there is a problem with FASTCOPY during a copy process. To diagnose if it is Fastcopy related you can diagnose the problem bu excluding Fastcopy for this step and rerun your job.
Using exclude function to turn off Fastcopy intercept
FastCopy processing can be disabled for a selected job step by including the following DD statement in the step:
//FCOPYOFF DD DUMMY
Note: This override is ignored if the output is a PDSE or program object library for which PDSMAN has interest (as defined by one or more PDSMAN Initialization Control Statements) and the input is also a PDSE or program object library.