On the UAG system, I'm importing appraisal data to existing object records. In the object editor there is a repeatable container called appraisal_info.
In many cases, the data includes multiple appraisals for a single object. So I have the appraisal_info container set to be repeatable, and the mapping setting to "merge on idno."
However, instead of adding a new instance of appraisal_info for each appraisal, the final appraisal simply overrides all previous appraisals.
In other words, the mapping setting is behaving like the "merge on idno with replace", which replaces existing data, as opposed to "merge on idno" which used to tack on new instances for all repeating fields.
Can you please take a look? I can email you mapping+data.