I have enabled both Traditional Chinese (zh_TW) and Simplified Chinese (zh_CN), and there is a bug that both of these locales actually use same language which is zh (Chinese). Which means that when updating data in the content app for either simplified or traditional Chinese it overwrites each other as the language used to store the data in jcr is zh, but not zh_TW or zh_CN.

For example if i have lets say productName form field, and add value to it in English, Simplified and Traditional Chinese, JCR does below:

• productName=productA
• productName_zh=產品A

Expected:

• productName=product1
• productName_zh_CN=产品1
• productName_zh_TW=產品1

This problem was not there with 5.3.8 seems to be introduced after. I am running now on 5.4.2, note i am not using site module, my locales are enabled under:
/server/i18n/content/locales/zh_TW
/server/i18n/content/locales/zh_CN

Originally posted here

Also please let me know in what version this was introduced, i will attempt downgrading