'An error occurred while saving the draft' when trying to save the 'Home / Places & Tastes / Tastes / Polish cuisine' content. (Content ID: 81, Location ID: 82).
Clean install of ezstudiodemo (1.5.0)

steps to reproduce (1.5.0):
1. Log in as admin on /ez.
2. goto 'Home / Places & Tastes / Tastes / Polish cuisine' content
3. click 'Edit' on the right menu
4. click 'Save' (no need to change anything)

the error message 'An error occurred while saving the draft' will show up on the bottom.

after some investigation the possible reason could be sql data in Resources/installer/sql/demo_data.sql

"An exception occurred while executing 'INSERT INTO `ezcontentobject_attribute` (`contentobject_id`, `contentclassattribute_id`, `data_type_string`, `language_code`, `version`, `data_float`, `data_int`, `data_text`, `sort_key_int`, `sort_key_string`, `language_id`, `id`) VALUES (:placeholder1, :placeholder2, :placeholder3, :placeholder4, :placeholder5, :placeholder6, :placeholder7, :placeholder8, :placeholder9, :placeholder10, :placeholder11, :placeholder12)' with params [81, 360, \"ezstring\", \"eng-GB\", 5, null, null, \"Senior Editor\", 0, \"\", 3, 514]:\n\n

SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '514-5' for key 'PRIMARY'",