Version history and comments not migrated in new versions of Confluence

Hi all, 

We noticed when exporting site XML files from our Confluence (version 8.5.4) that we no longer saw version histories or comments appear post-migration. After some detective work, we found that some of the page references have changed and thus don't get picked up when running the XWiki migrator applications. In particular, the Page object referencing the ID of related items (comments, version) is different from previous Confluence versions than more recent ones.  

For example, the following fields/properties are missing:

# comments
</collection>
<collection name="comments" class="java.util.Set"><element class="Comment" package="com.atlassian.confluence.pages"><id name="id">170632641</id>
</element> 

# page history
<collection name="historicalVersions" class="java.util.Collection"><element class="Page" package="com.atlassian.confluence.pages"><id name="id">170632562</id>

To fix this, we had to inject the missing metadata back into the files (via Python script) in order to successfully get all of the desired content to make it over the Confluence>XWiki bridge.