sorry, it's right now.
For all readers: The error I get is very similar to what Nicolas got (but in English). It is:
An unexpected error occurred. If you continue to receive this error please
contact your Tableau Server Administrator.
uncaught exception: Invalid Tableau Format Type
unfortunatly, it'was right for my workbooks load.... not for the error.
I still get the message, and i'm realy in a deadlock ....
help would realy be appreciated
they said it was really an error, correction in 2019.2.5
Hope i'll be able to test it in few weeks.