in your trailer's paperwork there should be something from the tent end manufacturer, i think it was T.J. Snuggles.
it states that you should pre-wet the tent ends before camping. this is common with popups, also.
the thread is supposed to get wet, swell and then be tight afterward.
if you had the furnace on and didn't have air moving at nite or vents open, then it could have been condensation.
if you think it's the seams and you did pre-wet as per instructions, then you may want to use a seam sealer.