AEM MongoDB upgrade to 6.3 fails with document size error

04.10.2017 18:45:54.104 *INFO* [oak-lucene-1] org.apache.jackrabbit.oak.plugins.index.lucene.directory.IndexSanityChecker Local index directory content found to be valid for index [/oak:index/ntBaseLucene]. Stats Local: 0 files (0 B), Remote: 67 files (176.9 MB)
04.10.2017 18:50:03.503 *WARN* [DocumentNodeStore lease update thread (1)] org.apache.jackrabbit.oak.plugins.document.DocumentNodeStore BackgroundLeaseUpdate.execute: time since last renewClusterIdLease() call longer than expected: 6202ms
04.10.2017 19:28:47.394 *INFO* [Apache Sling Repository Startup Thread] org.apache.jackrabbit.oak.plugins.document.DocumentNodeStore Pushing journal entry at r15ee8b55e90-0-1 as number of changes (1199767) have reached 100000
04.10.2017 19:28:48.602 *ERROR* [Apache Sling Repository Startup Thread] com.adobe.granite.repository.impl.SlingRepositoryManager start: Uncaught Throwable trying to access Repository, calling stopRepository()
java.lang.RuntimeException: org.apache.jackrabbit.oak.api.CommitFailedException: OakOak0001: Failed to merge changes to the underlying store
at org.apache.jackrabbit.oak.spi.lifecycle.OakInitializer.initialize(OakInitializer.java:54)
at org.apache.jackrabbit.oak.Oak.createNewContentRepository(Oak.java:636)
at org.apache.jackrabbit.oak.Oak.createContentRepository(Oak.java:624)
at org.apache.jackrabbit.oak.jcr.Jcr.createContentRepository(Jcr.java:386)
...
at org.apache.sling.jcr.base.AbstractSlingRepositoryManager$4.run(AbstractSlingRepositoryManager.java:455)
Caused by: org.apache.jackrabbit.oak.api.CommitFailedException: OakOak0001: Failed to merge changes to the underlying store
at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch$InMemory.merge(DocumentNodeStoreBranch.java:522)
at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.merge0(DocumentNodeStoreBranch.java:185)
at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.merge(DocumentNodeStoreBranch.java:119)
at org.apache.jackrabbit.oak.plugins.document.DocumentRootBuilder.merge(DocumentRootBuilder.java:167)
at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStore.merge(DocumentNodeStore.java:1694)
at org.apache.jackrabbit.oak.spi.lifecycle.OakInitializer.initialize(OakInitializer.java:52)
... 8 common frames omitted
Caused by: org.bson.BsonSerializationException: Document size of 27544148 is larger than maximum of 16777216.
at org.bson.BsonBinaryWriter.backpatchSize(BsonBinaryWriter.java:376)
at org.bson.BsonBinaryWriter.doWriteEndDocument(BsonBinaryWriter.java:123)
at org.bson.AbstractBsonWriter.writeEndDocument(AbstractBsonWriter.java:302)
at com.mongodb.DBObjectCodec.encode(DBObjectCodec.java:132)
at com.mongodb.DBObjectCodec.encode(DBObjectCodec.java:61)
...
at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch$InMemory.merge(DocumentNodeStoreBranch.java:513)
... 13 common frames omitted