The surface temperature of the inside pane of glass is colder than the
dew point of the air in the room. Either you are running a humidifier
with too high a setting or you bought cheap glass, which is the most
likely answer. I just replaced my widows 2 years ago. The company had
a good reputation and was not the most expensive, but I got the most
expensive windows they had. It was worth the money. Note, the colder
it is outside, the more likely it is the condensation will occur, as it
makes the glass colder. Moisture levels outside will have less impact
than temperature outside.

Stretch