Raoul, have you filed a bug report with Tableau on this issue?
I'm seeing a number of TDE/data source issues cropping up with 10.3.x, and other odd issues as well.
No. Can you tell me where I can do that?
That should do it. You might want to search open cases, too, to see if anyone else has reported this. I didn't see anything on a quick glance, but you may have better luck.