On a paid Moz Pro account, every Tumblr that I look up - literally all of them - come back as PA 94. It doesn't matter what it is. Examples: seo.tumblr.com, internetmarketing.tumblr.com, xxx.tumblr.com - you name it, if it's Tumblr, it shows me 94. And there is no Spam Score rating. I included examples results below from horses.tumblr.com. Again I am in a Moz Pro account, not some other website calling the API.
Similarly, I'm seeing similar behavior with other 2.0 domains (Weebly, Webs, etc.) where all of them report the same PA for all subdomains in the domain. I think I first noticed this yesterday morning.
URL:
http://horses.tumblr.com
Authority
Domain Authority Domain Authority: Predicts this root domain's ranking potential in search engines based on an algorithmic combination of all link metrics.
99 /100
Page Authority Page Authority: Predicts this page's ranking potential in search engines based on an algorithmic combination of all link metrics.
94 /100
Spam Score:
https://moz.com/researchtools/ose/spam-analysis/flags?subdomain=horses.tumblr.com
Page Link Metrics
Just-Discovered
1 60 Days
Established Links Root Domains: Number of unique root domains (e.g., *.example.com) containing at least one linking page to this URL.
Total Links: All links to this page including internal, external, followed, and nofollowed.
27,966 Root Domains
2.9m Total Links