The styles ship with core/modules/system/css/system.css, so only some themes will provide custom styling for that.
The editor content doesn't ship with these styles, that's why alignment is visible or not.
Classes get added properly, so after saving the alignment works. Only inside the editor they're missing.
The styles ship with core/modules/system/css/system.css, so only some themes will provide custom styling for that.
The editor content doesn't ship with these styles, that's why alignment is visible or not. Classes get added properly, so after saving the alignment works. Only inside the editor they're missing.