I replaced the fitting with a 90 degree elbow and slightly rerouted the vent hose. Tank is now filling properly with a strong flow of air coming out the vent.
If anyone is interested the fitting is a nylon hose barb from Lowes, size 1/2 inch hose barb X 1/2 inch MIP.
After filling the tank I can see why some have had issues with it dropping out. Altnough I will rarely be traveling with a full tank I think I will research the threads on adding support straps.
Cedar Creek Lake, Texas
2016 Wildwood Xlite 171 RBXL
2016 Ram 5.7L crewcab.