On the R&M Birdy Touring with only a 10s derailleur (now 11s on mine), the derailleur housing in in three parts and uses the bottom openings of both the main frame and rear swing arm. At the opening of the rear swing arm there is a special housing stiffer and made of a kind of spring that prevent the housing to bend and make a loop, instead of sliding inside the main frame, when unfolding the rear swing arm (Pacific Cycles didn't put this special housing on the Titanium Birdy and sometimes the derailleur housing makes a loop when unfolding the rear swing arm).

Are you sure that on the Pacific Cycles Birdy Touring with SA 3s rear IGH hub+derailleur, the bottom cable+housing is for the 3s of the IGH hub and not for the derailleur like on the R&M Birdy Touring?