There is another issue with export (to HTML) that I found out only now to be related with indentation: The example below exports like expected but when all lines below project are indented (by two spaces) then the lines BEGIN and END are also exported.
* project #+BEGIN: columnview :maxlevel 3 :id ddb38905-fcbb-473b-99ef | Task | Days | |---------------------+------| | *** Total of Effort | 1 | | ***** feature | 1 | #+END: Michael