These very likely are live connections from Tableau rendering of dashboards. Have a look at your datasources tab and see which datasources have live connections to SQL Server.
Thanks for your reply, Jeff.
I doubt if that's the case as we only have 2 live connections only to 1 workbook that were ever accessed.
To add on to the information provided before:
This issue started after we upgraded to Tableau 10.3.2.
The queries don't look like extracts. The Queries look like they are populating calculation results and doing indexes.
CREATE INDEX [_tidx_#Tableau_1103_2_Connect_1a] ON [#Tableau_1103_2_Connect] ([COL])