Please post some lines from the dnsmasq log at /var/log/pihole.log showing this behavior. For each query, there should be a query line, a forward line (only applicable if Pi-hole had to forward the domain for resolution), and a reply line.
To provide some lines to look at, run the following commands first (using domains known to be in your gravity list or local domain blocks) from the Pi terminal and post these results as well.
nslookup reddit.com 127.0.0.1
nslookup www.cleansite.us 192.168.1.96
Then, from the client on which you are seeing things not being blocked, from the terminal or command prompt on that client and not via ssh to the Pi, run the following and post the output:
Also, when I load reddit once, it loads fine on my PC but says it was blocked on the Pi. It's definitely a problem with my PC because it works just fine on my phone.