First of all, thank you for such a huge update!
And upon checking file integrity, I see the following log messages.
[database name] > [document name]|Invalid File Integrity, checksum is different.|
[database name]|Verified integrity of 1106 files successfully, checksum of 4 files different.|
So, could you explain what it means? And how can I fix it?
Have you read the appropriate section of the handbook (specifically page 137) and are your files (or specifically the four listed in the log) indexed?
I didn’t know that the handbook has also been updated. Thank you for pointing it out. And all my files are imported.
The documentation is updated with every release, even if it’s merely the Release Notes (which it never is) 
Hold the Option key and choose Help > Report bug to start a support ticket.
Yes, I did. Thanks!