2017 3791RD Rear A/C condensate collecting on roof

[JamesDean334]

I was on the roof of our unit sweeping off slides before bringing them in and I noticed water (A/C condensation) standing around the perimeter of the rear A/C. There's a "valley", for lack of a better term, that's about 1/4~3/8" around the whole unit. Is this normal? This was the first time I'd gotten on the roof after the A/Cs had been on for an extended period. I'd never noticed this valley before and wouldn't have noticed it this time had it not had standing water in it. There is no leak inside the camper in this or any other area. My plan is, now that it's back in the barn, to get back up there and check for any obvious reason for the valley. If nothing seems to be wrong, should I fill the valley with leveling Dicor, apply Eternabond tape to the perimeter to cover the valley and create a slope for runoff, both, or leave well enough alone??