why "errors validating the config synchronization" when UUID's match? I'm moving a d8 config from dev to stage and I have edited system.site so that the primary UUID on the stage system is identical to the dev system; and yet drush still reports: "There were errors validating the config synchronization."

This is an initial import; so it wants to replace almost all the objects on the stage site with objects from dev which differ only by UUID. There is almost no data (just site name, etc.) This used to work fine under 8.0.0-beta12; but I recently updated to 8.0.0-beta15 (which may or may not be significant). I'm using drush tag 8.0.0-beta14.

# grep uuid configs/from_dev/system.site.yml 
uuid: c3b4a4a7-e8ab-44d2-b349-73dc5a8dea63
# drush8 @iron.stage cget system.site | grep uuid
uuid: c3b4a4a7-e8ab-44d2-b349-73dc5a8dea63
# 


I checked the whitespace and rebuilt the cache.

# drush8 @iron.stage cim from_dev
 Collection  Config                                                Operation 
             system.menu.account                                   create    
             block.block.bartik_breadcrumbs                        create    
             block.block.bartik_content                            create    

       blah.. blah.. blah..

             block.block.bartik_breadcrumbs                        delete    
             system.menu.account                                   delete
Import the listed configuration changes? (y/n): y
exception 'Drupal\Core\Config\ConfigImporterException' with message      [error]
'There were errors validating the config synchronization.' in
/usr/local/www/d8_iron_stage/d8/core/lib/Drupal/Core/Config/ConfigImporter.php:730
Stack trace:
#0
/usr/local/www/d8_iron_stage/d8/core/lib/Drupal/Core/Config/ConfigImporter.php(517):
Drupal\Core\Config\ConfigImporter-&gt;validate()
#1
/usr/local/www/d8_iron_stage/d8/core/lib/Drupal/Core/Config/ConfigImporter.php(464):
Drupal\Core\Config\ConfigImporter-&gt;initialize()
#2 /usr/local/src/drush/commands/core/config.drush.inc(622):
Drupal\Core\Config\ConfigImporter-&gt;import()
#3 /usr/local/src/drush/includes/drush.inc(719):
_drush_config_import(Object(Drupal\Core\Config\StorageComparer))
#4 /usr/local/src/drush/includes/drush.inc(705):
drush_call_user_func_array('_drush_config_i...', Array)
#5 /usr/local/src/drush/commands/core/config.drush.inc(600):
drush_op('_drush_config_i...',
Object(Drupal\Core\Config\StorageComparer))
#6 [internal function]: drush_config_import('from_dev')
#7 /usr/local/src/drush/includes/command.inc(359):
call_user_func_array('drush_config_im...', Array)
#8 /usr/local/src/drush/includes/command.inc(210):
_drush_invoke_hooks(Array, Array)
#9 [internal function]: drush_command('from_dev')
#10 /usr/local/src/drush/includes/command.inc(178):
call_user_func_array('drush_command', Array)
#11 /usr/local/src/drush/lib/Drush/Boot/BaseBoot.php(62):
drush_dispatch(Array)
#12 /usr/local/src/drush/drush.php(70):
Drush\Boot\BaseBoot-&gt;bootstrap_and_dispatch()
#13 /usr/local/src/drush/drush.php(11): drush_main()
#14 {main}
If you set the uuid to null into shortcut.set.default.yml it will also works ok.