PiHole says it's blocking Omegle, but the website loads anyway

[GD.Ritter]

Running PiHole on Raspberry Pi 2B with Router set to use it as DNS for all endpoints. My 12 year old son has been getting into unsavory conduct on the site omegle and I want to block it. It's not just simple pornography but predatory type people telling him bad ideas. I want to ensure it's blocked 100%.

Expected Behaviour:

(spaces added to avoid hyperlinks)
website www . omegle . com (Or any variation that contains "omegle . com" should be blocked.

The following blacklist entries exist:

Actual Behaviour:

PiHole query log says it blocked it but the website loads anyways, even after flushing my local DNS.

Query log reports various blocks, all are some variation of the below with a different number in the middle:

However the site still loads:

Debug Token:

[✓] Your debug token is: https://tricorder.pi-hole.net/jrj129046e

[jfb]

If the website continues to load, it is likely that the client on which the browser is running has another DNS resolver available and some of the DNS traffic is not going through Pi-hole.