Hi!
Thank you for your kind words and the proper details, I think I managed to solve the issue.
Indexing files can be an exhausting operation, and the indexing failed, because the default number of items to index per iteration is set to 25. Basically the server was not able to process that many files at once. I have changed that option from 25 to 2, here: https://i.imgur.com/YQZ5yXW.png
I completely forgot to include this information in the documentation, sorry about that, I will make sure to add it soon.
The indexing now finished successfully, with 12848 keywords, which sounds correct to me: https://i.imgur.com/W8kPaxt.png
I hope this helped!