Some bad case like www.edu.cn

[likohank]

www.gov.hk, www.edu.cn, www.gov.cn
show wrong result.

[john-kurkowski]

What is your expected/actual?

However, I'm thinking this is not an issue in this project. See this FAQ entry.

Note the PSL includes all 3 of your examples specifically. Here's gov.hk, for example.