When migrating from 5.7 to 6.2.3 it has been reported that field validation is being triggered for fields which are empty but not required.
For example, if I had this configuration is Magnolia 5.7:
In 6.2 I need to update the pattern to:
validators precede "required: false" property now, this means that conversion of validators should be updated here: info.magnolia.ui.form.field.definition.migration.AbstractConfiguredFieldDefinitionConverter#convertValidators
(also emailValidator should be revisited to have possibility to have unrequired email field in M6 ui)