Unauthorized: Cannot create FormStringField

[zopyx]

Plone 5.0.5, logged in as admin, trying to create a FormFolder (PFG 1.8.1):

2016-07-08 11:47:33 ERROR Zope.SiteErrorLog 1467971253.620.400135526887 http://omicron.fhlb.ch:5080/omicron/de/portal_factory/FormFolder/formfolder.2016-07-08.2521974078
Traceback (innermost last):
Module ZPublisher.Publish, line 127, in publish
Module ZPublisher.BaseRequest, line 508, in traverse
Module ZPublisher.BaseRequest, line 352, in traverseName
Module ZPublisher.BaseRequest, line 135, in publishTraverse
Module Products.ATContentTypes.tool.factory, line 222, in getitem
Module Products.ATContentTypes.tool.factory, line 77, in _createObjectByType
Module Products.CMFCore.TypesTool, line 552, in _constructInstance
Module Products.PloneFormGen.content.form, line 7, in addFormFolder
Module Products.PloneFormGen.content.form, line 866, in initializeArchetype
Module Products.ATContentTypes.lib.constraintypes, line 290, in invokeFactory
Module Products.CMFCore.PortalFolder, line 292, in invokeFactory
Module Products.CMFCore.TypesTool, line 833, in constructContent
Module Products.CMFCore.TypesTool, line 309, in constructInstance
Unauthorized: Cannot create FormStringField

[keul]

@zopyx while I'm reporting other issues I tried to reproduce this without luck (same Plone and PFG versions)

[zopyx]

Also can't reproduce it again since we kicked PFG from this particular project...closing :-)