Dark Reader was overriding the value and hiding the issue.
@@ -8,7 +8,6 @@
height: 100vh;
width: 100vw;
background-image: url(test-image.jpg);
background-color: rgba(0, 0, 0, 50%);
background-position: center;
background-size: cover;
align-content: start;
The note is not visible to the blocked user.