After upgrading to Safari 14, many of our customers noticed that 1Blocker's Safari extension icon turned accent tinted.
It actually happened to all third-party apps that provide extensions for Safari. The thing is that Safari 14 sets the color of all icons made by third-party developers to the accent color chosen in the macOS settings. So in most cases, the extensions have blue icons now since it's the most popular accent color configuration.
We understand that it might sometimes be distracting, but it's currently out of our control. However, if there's a way to customize the icon's appearance, we will consider adding such an option in the future.