Superelement INTERNAL PROGRAMMING ERROR 8008 rergdc

I am trying to perform a superelement in a model (acquire the .pch file) and I am able to do it with simple, small models (examples, tutorials, etc); none the less, when moving to big models I'm acquiring the following error:

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A fatal error has been detected during input processing:

*** INTERNAL PROGRAMMING ERROR # 8008 ***
CHECK detects overwriting of data block: rergdc.
* DATAMANAGER ERROR in subroutine "datamx".


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I am performing the same steps as the tutorials, ending with the same card (Param EXTOUT), 1 Load Case and BCs with ASET type, but still having the same error across models.

Any idea what may be happening?