I noticed a small moist patch of the floor near a radon mitigation system. However, I suspect that it has little to do with the radon system but was due to failed caulking at the cove joint, as there seems to be dirt in a small segment of the caulking.

A recent heavy rain likely raised the water table so high that even though our sump pump worked properly, there was still a small amount of water seeping in.

Is my assessment right? If so, what is a good caulk chemistry to use?

There are suggestions such as

Quikrete polyurethane sealant,

silicone caulk,

latex-based Drylok waterproofer.

Updated: A picture of the sump pump. The sump pit is 19 inch in diameter and pretty deep, but the float makes the pump to operate only between a limited depth (as you can see from the water marks in the picture).