Thanks, everyone.
I use Dicor and know it is the cables because I've seen it. I fixed it once before & that lasted a couple years. Since I have 2 cables going through the hole, I'm thinking it's tough to get a good seal between the 2 & it wicks between them. I really think it has to do with the darn Texas heat and age of the Dicor also & I just need to replace it more often. I had an RV repair shop owner tell me that caulking should be replaced every year if the RV sits in the Texas sun. Not a bad idea to protect our baby!!
Here is what I'm building to protect against that sun & I'm going to replace all caulking here in the next few months that I didn't get to this past fall. :)