OK we need a test, so here goes:
Start a new game. TGM & TCL. Go straight to the doorway that leads to Bailey's Crossroads but don't go in. Save here. This save should be used at every point afterwards when I type "go back to your save."
First run through: No stash packs enabled. Not even in your data folder. This *should* go off without a hitch and will be our 'control' test. Make a note of what happens and go back to your save.
Second run through: Courier's Stash. The result should be the same as using all 4 packs. Doesn't really help with the issue at hand other than getting a confirm on the above post. Make a note of what happens and go back to your save.
Third run through: Caravan Pack only. Make a note of what happens and go back to your save.
Fourth run through: Classic only. Make a note of what happens and go back to your save.
Fifth run through: Mercenary only. Make a note of what happens and go back to your save.
Sixth run through: Tribal only. Make a note of what happens and go back to your save.
Sadly if this doesn't nail it down to which pack we may have to do more than 6 tests.. with different combinations.