1x1 subscenes created by PixEx cannot be opened in BEAM

When using PixEx to create 1x1 subscenes, these subscenes cannot be opened in BEAM. The exception is:

java.lang.IllegalArgumentException: Invalid number of points in LinearRing (found 3 - must be 0 or >= 4)
at com.vividsolutions.jts.geom.LinearRing.validateConstruction(LinearRing.java:108)
at com.vividsolutions.jts.geom.LinearRing.<init>(LinearRing.java:100)
at com.vividsolutions.jts.geom.GeometryFactory.createLinearRing(GeometryFactory.java:339)
at com.vividsolutions.jts.geom.GeometryFactory