Possible conflict on Invitation.WebHome when upgrading from 8.4.6

It happen randomly depending on the order in which classes are loaded in R1008010XWIKI10092DataMigration.

The reason is that this migration add new properties directly in the database but if those properties are added to a document containing a class you can end up in a situation where the cache contains the document without those new properties so it's like they were never added for the following code which manipulate this document (here the XAR install).

The same is true for any xlcass containing an object which is missing some properties.