Interesting indeed. My Marantz and Onkyo disable the subs in direct/pure direct. Stereo enables them, but also Audyssey too.
I also have Yamaha and pioneer and iirc they disable the subs in those modes. Huh...experiment mode, engage.
Ya know, iirc direct does allow subs for anything with .1. My manual says, direct mode plays back audio as recorded in the source. So for 2.0 subs should be off, but not movies.
Also wonder
@KEW are you using lfe+main?