Some revision contents can't be found. For example, look at the history of Sails of Care, where revision 4657503 can be seen at 07:46, 4 June 2018. Then click through to view it and get the following error:
The revision #4657503 of the page named "Sails of Care" does not exist.
It seems that not all of all database tables were copied across in the final switch over.