When configuring a trait with the following valueField configuration:

When modifying the value inside of the preview app, the first time I add a value, it isn't reflected in the trait. Every subsequent modification shows me the previous state, before my modification. For example:

will not have any values specified on the item. If I then modify the value to "bar" in the text field, the item's value will then be a list, with a single value: "foo".

This issue is present on both 5.5.12 and 5.6.8. It appears specifically when I use a multifield in the value field.

To reproduce:

1) Create a fresh magnolia instance on 5.5.12 or 5.6.8

2) Configure a trait that uses a multivalue field under the "valueField" configuration

3) Open the preview app and add a value for that trait. Observe that no value is actually set in the parameter converter.

4) Add a second value or modify the original value, thus triggering another submit. Observe that the first value is what appears in the parameter converter now, rather than the updated value.