Until two columns macro in a section one, an error occurs : "Section macro expect at least one column macro as first-level children"

Description

The Column20Macro throws an error when we put more than one column macro inside a section macro. This issue appeared in a 2.3.1 wiki version (Graphical Windows native installer) on a windows 7.

{{section justify="true"}}
{{column}} a {{/column}}
{{column}} b {{/column}}
{{/section}}

{{section justify="true"}}
{{column}} a {{/column}}
{{/section}}

Extract of the error

Failed to execute section macro : org.xwiki.rendering.macro.MacroExecutionException: Section macro
expect at least one column macro as first-level children
at org.xwiki.rendering.internal.macro.column.SectionMacro.execute(SectionMacro.java:78)
at org.xwiki.rendering.internal.macro.column.SectionMacro.execute(SectionMacro.java:25)
at org.xwiki.rendering.internal.transformation.MacroTransformation.transformOnce(MacroTransformation.java:174)
at org.xwiki.rendering.internal.transformation.MacroTransformation.transform(MacroTransformation.java:119)
at org.xwiki.rendering.internal.transformation.DefaultTransformationManager.performTransformations(DefaultTransformationManager.java:72)
[...]
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)