Too many things need to be investigated...but popping and cracking a few months later scream out "low humidity". Winter is the "dry" season (heating = drying).

What was the install method: glue, float, nail? How flat was the original parquet? Was there anything put between the two floors (craft paper, etc)?

First things first: check your home's humidity = 45% - 60% is a must. If you have no way of measuring it, that means it is "uncontrolled". Go ahead and buy a hygrometer and start measuring the humidity in the home. Old wood floors are well acclimated. New wood often has problems in homes that are "uncontrolled".

It's a hack approach.

The parquet floors should've been removed, prior to installation of the new floors.

gmail.com and my name is Joel