Could not adapt schema

Hi, my name is Artur and I work as an intern at an University in Brazil.

When someone is goint to edit some post in the institution site, the following error occours:

019-07-09 14:05:27 ERROR Zope.SiteErrorLog 1562691927.320.248646248048 http://localhost:8080/UFFS/pastas-ocultas/bd/campus-chapeco/cursos/mestrados/ppgelch/ppgelch/@@edit/++widget++form.widgets.processo_seletivo_em_andamento
Traceback (innermost last):
  Module ZPublisher.Publish, line 127, in publish
  Module ZPublisher.BaseRequest, line 508, in traverse
  Module ZPublisher.BaseRequest, line 332, in traverseName
  Module zope.traversing.namespace, line 112, in namespaceLookup
  Module plone.z3cform.traversal, line 60, in traverse
  Module plone.dexterity.browser.edit, line 58, in update
  Module plone.z3cform.fieldsets.extensible, line 59, in update
  Module plone.z3cform.patch, line 30, in GroupForm_update
  Module, line 141, in update
  Module, line 52, in update
  Module, line 48, in updateWidgets
  Module z3c.form.field, line 243, in update
  Module z3c.form.datamanager, line 102, in canWrite
  Module z3c.form.datamanager, line 66, in adapted_context
TypeError: ('Could not adapt', <Container at /UFFS/pastas-ocultas/bd/campus-chapeco/cursos/mestrados/ppgelch/ppgelch>, <SchemaClass>)

This error is very random, but it always occour when someone is editing something.
This error makes some fields (RelationChoice and RelationList) not load sometimes, but if we keep refreshing the page, eventually it loads. It's very strange.

When some fields don't load, this error appears, something with @@getSource.
But if we keep refreshing the page, the error will eventually dissapear.

We don't know what to do anymore.
Any help is appreciated.
Thanks for your time.