Stage thundermail hit with `NO_FM_NAME_IP_HOSTN` spamassassin rule

[MelissaAutumn]

My email wasn't hitting spam, but I feel like we might be able to take a look at this rule. This is from my fastmail inbox:

X-Spam-known-sender: no
X-Spam-sender-reputation: 500 (none)
X-Spam-score: 2.4
X-Spam-hits: ME_SENDERREP_NEUTRAL 0.001, NO_FM_NAME_IP_HOSTN 2.05, RDNS_DYNAMIC 0.363,
  SPF_HELO_NONE 0.001, SPF_PASS -0.001, LANGUAGES unknown, BAYES_USED none,
  SA_VERSION 4.0.1
X-Spam-source: IP='63.179.185.6',
  Host='ec2-63-179-185-6.eu-central-1.compute.amazonaws.com', Country='DE',
  FromHeader='com', MailFrom='com'
X-Spam-charsets: plain='UTF-8'

According to a brief interweb search NO_FM_NAME_IP_HOSTN's description is No From name + hostname using IP address. I think it might just be due to us using aws' domain name as a cname entry.