It looks like the formatter assigned to a label is lost, if the table is repainted (e.g. a row is added).
The label has a valueSource (ContainerValueSource) and a formatter to format the BigDecimal value as a formatted currency string (e.g. 8 becomes “8.00 €”)
As soon as an item is added to the underlying
CollectionPropertyContainer the format is lost and only the number (e.g. 8) is displayed.