Message Properties Map Incompletely Unmarshalled from marshalledProperties, Causing Selector Failure

We noticed messages not getting dispatched to consumers after adding a selector to our message consumers. It appeared that non-matching messages were accumulating in the cursor, resulting in eventual blockage.

Upon taking a heap dump of the broker, we noted that paged in messages had missing properties in the properties map that appeared to be present when examining the marshalledProperties field.

What could cause the properties map to go missing when the marshalledProperties field is populated? In comparing the marshalledProperties array (as a string) for a message missing the properties map with a similar message where the affected properties were present in the transient map, there seemed to be no difference in format.