From here: https://www.reddit.com/r/pihole/comments/f3jsoo/what_on_earth_happened_almost_450_clients_there/
The graph labels confused me in the beginning too. Maybe the titles could be tweaked for v5?
Queries over last 24 hours
Clients (over time)
to
Queries Forwarded and Blocked - over the last 24 hours
Queries by Client - over the last 24 hours
Or something similar to reduce the initial confusion?