This has been my experience as well. I have fixed a couple mis-markings myself, after careful examination of the accounts, because sth seemed a bit off.
As many of the 1-star reviews state, accounts that are obviously green are marked as red and vice-versa.
I don’t know if it is a moderation issue. The app was dead-accurate for many years, and in the docs they stated they do some manual confirmation as well. It could be sth even more technical with their filter. We can’t know.
But the important thing is that it is up to us, the users, to correct mistakes were they are found, or even deliberately introduced by faschists. Shinigami Eyes always was a crowd-sourcing app.
If the crowd stops submitting quality data, then the app will go, indubitably, ashtray.
That sucks. I’m still going to use it though because it saves a lot of time to help filter out transphobes but like any good thing there will be people trying to ruin it.