Export Data No Longer an Option for Users?

It seems like some users in your organizaiton don't have the permisison on the underlying dataset.

When the content owner shares the content to this user, the "Allow users to build new content using the underlying datasets" was probably not checked.

To fix it, the owner can grant build permission to these users through manage permissions page of this underlying dataset.

For more informaiton, please read https://docs.microsoft.com/en-us/power-bi/service-datasets-build-permissions#build-permissions-for-shared-datasets