When I do a LOOK SUBSCHEMA, I see a compile date of 2012. When I display the Subschema in the subschema compiler, it has a LAST UPDATE of Jan 16, 2018 which is when I did the modify/generate.
Why are these dates different?
Release: IDADSO00100-18.5-ADS-for CA-IDMS
The LOOK indicates the load module date. So, when that subschema load module was generated, the date was 2012.
When you display the source in the dictionary, the date the source was last updated was 01/16/18.
If you were to generate that subschema, and vary it new copy, then run the LOOK, you should see the date updated.