Jorropo:
Is this expected or I am doing something wrong?
Have a look at the documentation of DNSPort: https://2019.www.torproject.org/docs/tor-manual.html.en#DNSPort
Tor's DNSPort is rather limited, if you need more I recommend to use an encrypted DNS protocol like DNS-over-TLS or DNS-over-HTTPS and route that over Tor, but be aware that your DNS resolution requests are linkable if you do not establish a new stream and connection for each resolution attempt.