Hi there,
Sam from Moz's Help Team here - thanks so much for reaching out!
So, a couple of things - when you disavow a link through Google, it doesn't actually remove the link, Google just stops putting SEO weight into it. So our crawler will still find the link. Unfortunately there isn't a way in Link Explorer to "disavow" a link yet so we will still show it.
Disavowing a link doesn't take it away from our tools, so they will still appear as backlinks to your site. The fact that Google disregards them in relation to your site does not take them off the sites they are on, so best practice is to approach the webmaster first and request the link be removed. If you get no response then disavow with Google:).
I also want to note a couple of things about your DA drop in general - overall, seeing your DA drop is a fairly common problem and can be attributed to a few things:
1.Links we previously discovered are now marked as lost.
2. You've earned more links, but the highest authority sites have grown their link profile even more.
3. The links you've earned are from sites that we haven't seen correlate well with higher Google rankings.
4. We've done a better or worse job crawling sites/pages that have links to you (or don't).
It's a bit difficult to isolate the exact cause of what happened without your own SEO consultant or developer being able to take a dive into this, but you can definitely read more specific information here if you'd like to understand more about the process:).
Something else to note is that on March 5th, we rolled out an entirely new DA calculation method, which affected the DA of many sites. You can read more about this update here https://cloudz.click/domain-authority-2.0.
Do let us know if we can help with anything else!