After a rigorous experimenting on this topic for 3 months or so, I was able to find the solution.
Posting it for the community users.
- disabled xmp write back workflow launcher - enabled out-of-the-box "Set last modified date" workflow launcher - created a translation integration config. Go to Tools - Cloud Service - Translation Cloud Services - In this config, make sure you uncheck the box for translating assets, and only enable it for tags and metadata (if desired). Also, set it to "Auto Execute Translation" - apply that config to the folder containing your language folders. - When doing translation for the first time, need to create translation project, and project can be re-used for all future translations. multi-lingual projects can also be used if needed.