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Overview of the issue
When using LearnDash LMS with WPML, course progress and user enrollment is not synchronized between the original and translated versions. As a result, users who complete a course in one language will not see their progress reflected in its translation.
Workaround
There is currently no viable workaround available for this issue. Syncing users and progress between translated courses requires a custom implementation from LearnDash team.
We are aware of this issue and we are in contact with LearnDash to push for a proper implementation.