In some scenarios, you may find that your translations are being returned either untranslated (inbound messages) or translated into a different language from your conversation selection (outbound translations).
As you notice, although the language selected for the customer is Chinese simplified, the messages are not translating entirely or translating into a different language.
This is caused by a previous conversation existing with the same label ID as your current one, where another language was used. In this case, you or another agent labeled a conversation with the ID "11223344" before, and requested at least one translation to German. Unbabel will remember that language from the first conversation, and set it in stone. All conversations created with the same ID will see the same issue.
To work around this, you need to archive the conversation and create a new one with a slightly different label, ideally something that still allows the conversation to be easily identifiable. In this example, something like 11223344-1, 11223344', 11223344_, etc.