It looks like your "cable patch" has simply come unglued. Something you might want to consider is that if you try to replace them, to do the job correctly, you'll need to disconnect the cables so you can "slip the patch onto the cable". The alternative is to cut the patch and slide it over the cable, leaving a gap that can leak.
Neither is a "good choice" when the current patch is serviceable, but just keeps falling off.
You can buy "automotive trim adhesive" in a tube from most auto stores. If you clean the trailer sidewall and the patch well, apply the adhesive both to the patch AND to the trailer wall, let it dry until it's "tacky", then press the two together, you can often "get a strong bond that will last"....
IMHO, it's better to "reattach the existing seal patch" than to rip it off and replace it with another one that's got the same adhesive on it as the one that just fell off.....
That said, if you're intent is to replace them, they cost about $10 each. At Trekwood, they're $39 for a set of 4 and the shipping will increase that cost...
You can buy 1/8" thick neoprene rubber that's 2" wide and 10' long for $16.
https://www.amazon.com/Neoprene-Rubb...a-911360209812 A tube of "quality trim adhesive" is around $5 at any automotive parts store. That's significantly cheaper than the OEM alternative that's very likely going to fall off "just as fast as these ones did.....