Should I be concerned with this?

They probably just patched it until they had time to do it right.I would put that chore at the top of my list for that trailer and some good weather.As far as leaks go,most trailers do at some point whether noticed or not.All the twisting/bending and bumpy roads will crack the best of seals and it's the little leaks(hair line) that get you.

I wouldn't be concerned except for the fact it needs a good reseal.Some people just patch what they can see, others re-do it all..