When translating pages that reference experience fragments, content is not being translated.
AEM 6.3 is shipped with a known product bug that causes translations of pages with experience fragments to fail.
This issue is resolved in AEM 6.3.1 (SP1, "Service Pack 1"). Install AEM6.3 SP1 from:
Another known cause of this issue is when the translation configuration is missing the experience fragment resource type. To fix this issue, follow the steps below: