Sink faucet dripping after a couple hours

[tumbleweed29]

We recently had our bathroom renovated and the contractors had installed new plumbing and two new Toto sink faucet fixtures in the vanity. When the water is shut off, there's no leak detected but usually 7+ hours later, I'll see a little puddle in the sink and a water droplet on the tip of the spout. All new hot and cold cartridges were replaced on both faucets. A new water pressure regulator was put in and set at 50psi, which is well under the 80psi that the faucet can run at. Not sure where to go from here, is it the faucets or a plumbing issue? Both faucets are acting the same way. My contractor has no clue to why this is happening. Any ideas?

 

[Matt30]

Could it just be residual water draining from the spout?

 

[tumbleweed29]

I thought residual water drips out right after you turn off the water and by overnight the sink should become bone dry? I find it awkward that there's no initial drip but after 7+ hours it starts dripping. I don't see this happening in our other faucets in the house.