The first picture I wasn't too sure what was going on, is the flaring at the base of the part, all the way to the right?
The flaring could be from a thin wall section opening up after ejection.. Adjusting cooling time (more or less) could help.. As well as playing with pack pressure and ejection settings (slow/fast etc.) But it could also be a part design flaw..
Also since you mentioned it's a cap, it could have some sort of unwinding core torsion-type flaring going on if there are threads on the part.

The second picture looks like delamination maybe? If the steel checks out okay, first thought was to play with the melt temp and mold temps to see if you can make better or worse.. But it could be a few different things