Without looking at the actual code I assume the following:
I believe this has to do with the fact that Direct Call rules were a concept born in DTM, which has now been replaced by Launch. Since the global variables are an Analytics concept, the code used to set and send these into Analytics is likely only implemented in the the s.t and s.tl functions.
Since Launch is attempting to be as efficient as possible it might not be running the code required to include the global variables.
If this is the case and you'd like that functionality to change. Please submit or vote on an idea in the Launch Ideas section of the community.