Welcome to the forum, we are also from PA.
As for your question, I haven't seen anything like that in my experience but, I am SURE someone else probably has.
It almost looks like the one end that has the flares is some sort of cap.
Is the left side fitting a female threaded end and then the right side fitting a cap of some sort?
Is your 28BH brand new? If so, might want to go around and check all fittings to make sure they are tight.
I recommend it as a yearly thing, these trailers take a beating going up and down the road (especially some PA roads). Things loosen up. If it's new you would think it's good from the factory but, fact is in alot of cases it's probably pretty bad as far as tightness goes.
I'm sure someone else will chime in with exactly what it is but, enjoy your outing!
2012 Keystone Sprinter
Still sticking around for the good people and advice.