Has anyone else noticed that after the Toto Eco Drake's flush is finished it has a loud "shquwap" noise. It's right at the end, after the tank has filled back up. I'm thinking it's the water turning off?

At any rate it's quite startling and I'm hoping someone can tell me how to fix it, or can tell me that they replaced a part(s) and it is not quiet.

Or maybe someone out there has another 1.28 GPF toilet that works as well as the Eco Drake only more quietly.

For anyone else who wants a quiet toilet the Toto Aqua is near silent (big or small flush) and it works great! - but personally I prefer the Eco Drake's 14 5/8 height over the Aqua's 15 1/4 inches.

Thank you for your help!
Charles