Redactor source plugin working on Text field but not on a Text field in Matrix I'm on 2.6.2988, I have a text-block in my entry with standard Redactor settings enabled showing the source-button in the menu.

In the same entry I have a Matrix field with text-block with standard Redactor settings but the source-button is not showing.

Is Matrix using a different config?
in german settings look carefully at the Redactor-Konfiguration , if you select Standardwert it uses Simple.json and not Standard.json.