I'm trying to get help diagnosing what the issue is. I am re-caulking the area around my kitchen sink. Since the sink is a top mount, and the piece of countertop on the side is severely damaged, I thought I'd just use caulk to basically fill up completely and create a flush surface with the top edge. In other words, a REALLY thick layer.
To prepare adequately for this, I removed the old caulk, cleaned, and let it dry fully over 24 hours. Then I put on a thick layer, dried it for 24 hours. Then I put on a thinner finishing layer to smooth it out, and again let it dry for 24 hours. (While I know it's not ideal to do caulk over caulk, I also know it should work if the old caulk is still in good condition; and in this case, it was fresh!)
I started using it today, and noticed it's flaking away. See photo. On the caulk only piece, you'll see where it looks kind of sandy, and then also you'll notice even the thin finish layer that was applied directly to the sink (that was clean/dry) is flaking off.
Trying to figure out what possibly the reason was. Was it... 1) too thick and needed way longer than 24 hours to dry, 2) wrong product? (resident manager gave me a product that is labeled for doors, windows, molding, etc., but said it's fine to use. it's latex plus silicon, doesn't feel very rubbery like caulk I'm more used to, felt almost chalky like... spackle?), 3) other reason entirely?