If they hadn’t visited Thailand in 2002, they wouldn't be living there now.
Here why the past perfect form was used at a specific time?
I've learned that the perfect form shouldn't be used at a specific time. Here the sentence invovles "in 2002", so is the tense correct? I've never seen this.
[Tests of conditionals:if] : https://dictionary.cambridge.org/zhs/plus/quiz/%E8%AF%AD%E6%B3%95/conditionals-2