Hi,
Thank you for the details!
The menu items were registered correctly, but somewhere there is a conflict with either another plugin, or one custom code, I could not locate where. I logged in via FTP and made a simple change to maybe bypass the issue, and it seems to be working okay now.
I will make sure to include that in the upcoming release, althought I don’t know what the cause is, as everything is registered correctly.
As for the performance, I have applied the index table engine, as it was not enabled. The search performance should be much smoother now.