The DelegatingMultiValueSubnodeTransformer doesn't work well with i18n, since 5.4.2.

Given the following MultiValueFieldDefinition:

class: info.magnolia.ui.form.field.definition.MultiValueFieldDefinition
transformerClass: info.magnolia.ui.form.field.transformer.multi.DelegatingMultiValueSubnodeTransformer
field:
  name: text
  class: info.magnolia.ui.form.field.definition.TextFieldDefinition
  i18n: true

When I add a new entry to the multi-field in English ("en") and I switch to German
Then

1. the entry disappears (should be preserved, with blank value);
   I have to add it again to enter the value in German ("de")
2. when saving the dialog, only the German property text_de = "de" is saved.

There seem to be similar quirks when removing entries as well.

Several notes:

• DelegatingMultiValueSubnodeTransformer was working in 5.4.1.
• DelegatingMultiValueFieldTransformer still works in 5.4.2.
  • It is the superclass of the subnode transformer
  • It has undergone major changes in 5.4.2 (MGNLUI-3489); these changes are most likely causing this issue.