Hi i have toyota corolla GLi 2013 only 10 k driven. under warranty for 2 years from toyota indus.

A month ago i replaced my AC gas which was resuced to half for unknown reasons. i went to toyota frontier peshawar and after diagnosing they found out that half the gas was reduced so in warranty they filled fresh indus gas.
After a month now it started to give me unpleasent odour smell every now and then.

i have cleaned air filter and issue resolved somehow not 100 %.

Anyway to cut things short. yesterday i have noticed when i started my car AC for first time in the day, a bad burning rubber smell comes through vents for few seconds and then disappeared.

Again after driving for 15 mintutes in city it start hitting my nostrils again with plastic or rubber like burning smell and after a few seconds, disappeared.

kindly suggest what could be the reason.