There are reports in Registar’s comment section that Malaysia didn’t only redirect DNS traffic, but took active measures to block VPN, and MITM DoH where Cloudflare’s DoH returns local ISP certificate.
In fact, some ISPs like Maxis and Yes were already blocking VPN (I see a lot of complains on Lowyat.net about Maxis blocking VPN, and I was using Yes WiMax and experienced the blocking firsthand. I couldn’t connect to PPTP endpoints and L2TP endpoints caused the modem to disconnect from the network and reboot).
They were outright trying a MITM redirect attack on those using DOH. Many reported error messages saying that Cloudflare’s DOH server were practically returning the certificate for Telekom Malaysia’s DNS servers.
Even with many new technologies, I ralized that I not as safe and free as I want to be, maybe you too.