Should nmap still be sending reverse DNS record requests when I set the -n flag? If so, why?

I am using Tcpdump to read packets sent by nmap. I want to totally disable reverse DNS, so I don’t have any packets that look like:

<host>.<port> > _gateway.domain: . . . *.*.*.*.in-addr.arpa. (data_length)

However if I set the -n flag in foreign scans:

nmap -p <port> -n <foreign_ip_address>
nmap -sn <foreign_ip_address>

Or local scans:

nmap -p <port> -n <local_ip_address>/<subnet_mask_length>
nmap -sn <local_ip_address>/<subnet_mask_length>

Tcpdump says it is still sending a lot of requests for reverse DNS lookup.

There should be a way for me to totally disable this, right?