Possible ConcurrentModificationException when serializing sending a complete update

2026-02-19 06:52:36,271 [Replication serializing] ERROR r.i.m.DefaultReplicationSender - Failed to store the message [id = [19f419a7-1dc2-4bac-87ff-0676718e71c5], type = [entity_update], source = [<null>], date = [Thu Feb 19 06:52:36 GMT 2026], receivers = [<null>], ...] on disk. It will be lost. 
org.xwiki.contrib.replication.ReplicationException: Failed to store sender message with id [19f419a7-1dc2-4bac-87ff-0676718e71c5]
	at org.xwiki.contrib.replication.internal.message.ReplicationSenderMessageQueue.add(ReplicationSenderMessageQueue.java:230)
	at org.xwiki.contrib.replication.internal.message.DefaultReplicationSender.addSend(DefaultReplicationSender.java:148)
	at org.xwiki.contrib.replication.internal.message.DefaultReplicationSender.syncStore(DefaultReplicationSender.java:243)
	at org.xwiki.contrib.replication.internal.message.DefaultReplicationSender.store(DefaultReplicationSender.java:204)
	at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: org.xwiki.contrib.replication.ReplicationException: Failed to write on disk the data of the message with id [19f419a7-1dc2-4bac-87ff-0676718e71c5]
	at org.xwiki.contrib.replication.internal.message.AbstractReplicationMessageStore.storeMessage(AbstractReplicationMessageStore.java:256)
	at org.xwiki.contrib.replication.internal.message.ReplicationSenderMessageStore.store(ReplicationSenderMessageStore.java:136)
	at org.xwiki.contrib.replication.internal.message.ReplicationSenderMessageQueue.add(ReplicationSenderMessageQueue.java:228)
	... 4 common frames omitted
Caused by: java.io.IOException: Failed to serialize the document with reference [wiki:Docs.908d75c4-0d5f-11f1-add4-bdd1bf7811a0.WebHome()] and version [8.1]
	at org.xwiki.contrib.replication.entity.internal.update.DocumentUpdateReplicationMessage.write(DocumentUpdateReplicationMessage.java:211)
	at org.xwiki.contrib.replication.internal.WrappingMutableReplicationSenderMessage.write(WrappingMutableReplicationSenderMessage.java:38)
	at org.xwiki.contrib.replication.internal.message.ReplicationSenderMessageStore.storeData(ReplicationSenderMessageStore.java:119)
	at org.xwiki.contrib.replication.internal.message.ReplicationSenderMessageStore.storeData(ReplicationSenderMessageStore.java:48)
	at org.xwiki.contrib.replication.internal.message.AbstractReplicationMessageStore.storeMessage(AbstractReplicationMessageStore.java:253)
	... 6 common frames omitted
Caused by: com.xpn.xwiki.XWikiException: Error number 2001 in 2: Error serializing document to XML
	at org.xwiki.contrib.replication.entity.internal.update.DocumentUpdateReplicationMessage.toXML(DocumentUpdateReplicationMessage.java:237)
	at org.xwiki.contrib.replication.entity.internal.update.DocumentUpdateReplicationMessage.write(DocumentUpdateReplicationMessage.java:209)
	... 10 common frames omitted
Caused by: com.xpn.xwiki.XWikiException: Error number 2001 in 2: Error serializing XML
	at com.xpn.xwiki.doc.XWikiDocument.toXML(XWikiDocument.java:5226)
	at org.xwiki.contrib.replication.entity.internal.update.DocumentUpdateReplicationMessage.toXML(DocumentUpdateReplicationMessage.java:235)
	... 11 common frames omitted
Caused by: java.util.ConcurrentModificationException: null
	at java.base/java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1208)
	at java.base/java.util.TreeMap$ValueIterator.next(TreeMap.java:1253)
	at com.xpn.xwiki.doc.rcs.XWikiRCSArchive.<init>(XWikiRCSArchive.java:77)
	at com.xpn.xwiki.doc.XWikiDocumentArchive.getArchive(XWikiDocumentArchive.java:248)
	at com.xpn.xwiki.internal.filter.input.XWikiDocumentLocaleEventGenerator.write(XWikiDocumentLocaleEventGenerator.java:129)
	at com.xpn.xwiki.internal.filter.input.XWikiDocumentLocaleEventGenerator.write(XWikiDocumentLocaleEventGenerator.java:62)
	at org.xwiki.filter.instance.internal.input.AbstractBeanEntityEventGenerator.write(AbstractBeanEntityEventGenerator.java:131)
	at com.xpn.xwiki.internal.filter.XWikiDocumentFilterUtils.exportEntity(XWikiDocumentFilterUtils.java:334)
	at com.xpn.xwiki.doc.XWikiDocument.toXML(XWikiDocument.java:5223)
	... 12 common frames omitted