How to debug/fix Object 'TRFN::xxx' refers to the invalid object 'ROUT::' ?

Hi Gurus,

I have 0MATERIAL_ATTR transformation which activates successfully. However, when collecting in transport it fails with red error message

Object 'TRFN::05CF00F4I0YTYKCCPZLJHBPJ1OTAOPFM' refers to the invalid object 'ROUT::'

How do I find out which routine it is? I've looked through most transformation/routine tables in SE16 but am not able to identify the invalid object.

Is there a way to see what the transport logic is for validating these objects?

I have 2 routines in mappings only, but tables show up to 4 with different ID numbers, spanning versions A, M, D.

BW 7.3 recently upgraded from 7.0

Thanks in advance!

Gregg