Just to add my voice to this, I'm having the same issue. Tag a plain text note, search for that tag, 'no notes found'... even though I can find them manually!
I haven't had the patience to wait for an hour yet, so it may work a bit later, but this 100% slows down my workflow too.
See below, I'm searching for notes in my Action Pending notebook, but it's displaying a note from a completely different notebook.