Exporting a space that is associated to a SpaceGroup causes an error (lazy init exception)

The following exception is thrown when we attempt to export a space associated with a space group.

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com.atlassian.confluence.importexport.ImportExportException: Couldn't backup database data.
@40000000470e46b11d960b14 at com.atlassian.confluence.importexport.impl.AbstractXmlExporter.backupEntities(AbstractXmlExporter.java:183)
@40000000470e46b11d966104 at com.atlassian.confluence.importexport.impl.AbstractXmlExporter.backupEverything(AbstractXmlExporter.java:85)
@40000000470e46b11d9668d4 at com.atlassian.confluence.importexport.impl.FileXmlExporter.backupEverything(FileXmlExporter.java:75)
@40000000470e46b11d9670a4 at com.atlassian.confluence.importexport.impl.AbstractXmlExporter.doExport(AbstractXmlExporter.java:78)
@40000000470e46b11d96e9bc at com.atlassian.confluence.importexport.impl.FileXmlExporter.doExport(FileXmlExporter.java:41)
@40000000470e46b11d96f18c at com.atlassian.confluence.importexport.impl.XmlExporter.doExport(XmlExporter.java:25)
@40000000470e46b11d96f95c at com.atlassian.confluence.importexport.DefaultImportExportManager.exportAs(DefaultImportExportManager.java:112)
@40000000470e46b11d97283c at sun.reflect.GeneratedMethodAccessor1178.invoke(Unknown Source)
@40000000470e46b11d972c24 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
@40000000470e46b11d9733f4 at java.lang.reflect.Method.invoke(Method.java:585)
@40000000470e46b11d973bc4 at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:287)
@40000000470e46b11d97571c at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:181)
@40000000470e46b11d975eec at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:148)
@40000000470e46b11d9766bc at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
@40000000470e46b11d977e2c at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:170)
@40000000470e46b11d9785fc at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:176)
@40000000470e46b11d978dcc at $Proxy49.exportAs(Unknown Source)
@40000000470e46b11d97959c at com.atlassian.confluence.importexport.actions.ExportSpaceLongRunningTask$2.doInTransactionWithoutResult(ExportSpaceLongRunningTask.java:85)
@40000000470e46b11d97bcac at org.springframework.transaction.support.TransactionCallbackWithoutResult.doInTransaction(TransactionCallbackWithoutResult.java:33)
@40000000470e46b11d97c864 at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:114)
@40000000470e46b11d97d034 at com.atlassian.confluence.importexport.actions.ExportSpaceLongRunningTask.runInternal(ExportSpaceLongRunningTask.java:61)
@40000000470e46b11d97e7a4 at com.atlassian.confluence.util.longrunning.ConfluenceAbstractLongRunningTask.run(ConfluenceAbstractLongRunningTask.java:21)
@40000000470e46b11d97ef74 at java.lang.Thread.run(Thread.java:595)
@40000000470e46b11d97f744 Caused by: net.sf.hibernate.LazyInitializationException: Exception initializing proxy: com.atlassian.confluence.spaces.SpaceGroup#27197441
@40000000470e46b11d98129c at net.sf.hibernate.proxy.LazyInitializer.initializeWrapExceptions(LazyInitializer.java:64)
@40000000470e46b11d981a6c at net.sf.hibernate.proxy.LazyInitializer.getImplementation(LazyInitializer.java:164)
@40000000470e46b11d98223c at net.sf.hibernate.Hibernate.getClass(Hibernate.java:287)
@40000000470e46b11d982624 at bucket.core.persistence.hibernate.schema.TransientHibernateHandle.<init>(TransientHibernateHandle.java:35)
@40000000470e46b11d985504 at com.atlassian.confluence.importexport.impl.HibernateObjectHandleTranslator.objectToHandle(HibernateObjectHandleTranslator.java:25)
@40000000470e46b11d985cd4 at com.atlassian.confluence.importexport.impl.XMLDatabinder.unbind(XMLDatabinder.java:261)
@40000000470e46b11d9864a4 at com.atlassian.confluence.importexport.impl.XMLDatabinder.unbindAll(XMLDatabinder.java:279)
@40000000470e46b11d987c14 at com.atlassian.confluence.importexport.impl.AbstractXmlExporter.backupEntities(AbstractXmlExporter.java:173)
@40000000470e46b11d9883e4 ... 22 more
@40000000470e46b11d988bb4 Caused by: net.sf.hibernate.HibernateException: Could not initialize proxy - the owning Session was closed
@40000000470e46b11d989384 at net.sf.hibernate.proxy.LazyInitializer.initialize(LazyInitializer.java:47)
@40000000470e46b11d98d9d4 at net.sf.hibernate.proxy.LazyInitializer.initializeWrapExceptions(LazyInitializer.java:60)
@40000000470e46b11d98e1a4 ... 29 more