[Informational] INF-2017-005: Extract Refreshes can unhide columns
Summary: If you have any extracts on Tableau Server with hidden columns, when you refresh, the columns become unhidden.
This can lead to slower extract refreshes, larger extracts, slower viz performance, and making previously hidden columns visible to users.
See issue 670693 on https://www.tableau.com/support/known-issues.
Versions Affected : Tableau Server 10.2.3, Tableau Desktop 10.2.3