Further info. The revision that doesn't work properly per above (r61734) was changed to no longer use Babble-Class-2.2. After reverting back to the immediate prior revision that does use it (r55165), the mod works without issues.
The current r61734 has stopped tracking arrows on a character.
Standard vendor Blackflight Arrows being carried. Next to the PTReagentFu icon in FuBar, no numbers are displayed. Via the menu choice of "Reagents", the flyout menu has nothing showing in it, just a blank frame.