I would suggest putting a 4" wide Eternabond seal on that seam, and the one in the back too. Scrape off a bit of the caulking if there's too much but if the tape sticks to either side of the seam without being on any of the caulking, that's good too so it can just be covered. The Eternabond won't stick to most caulking but sticks like crazy to roofing products. And the
Put mine on in March of '16 and it's still holding well. Also put it on my other RV back in '06 with great results too. Plus it's made to prevent leaks in RV roofs. Amazon carries it along with many others. I've not had to do hardly any maintenance to the Ebond applications over 16 years of use. Occasionally though.
I've also added it to the roof edge hopefully to prevent the roof from blowing off in a strong wind. Here's my articles about adding the tape to front, back, and side seams, there's no ads or anything:
Roof and Roof items...
The other common water entrance is from the running lights outside on the front endcap. Run a bead of clear silicon around them.