Enable removing the related table from ArcGIS Online Web Scene.

Alternate Workflow

The ArcGIS Online Assist could be used as a workaround to delete the table from the JOSN file of the layer as the following:

• Navigate to this URL: https://ago-assistant.esri.com/.
• Sign in using the ArcGIS Online account.
• In the search box, type the name of the problematic web scene that has the table although the layer was deleted. 
• Click on the drop-down list next to 'I want to...', then choose 'view an item's JSON'.
• Using your keyboard, hit ctrl f, then search for table.
• In the Data section of the JSON, copy the JSON to a notepad as a backup.
• In the Data section, click on the edit icon, then delete the table section. Check the following as an example:

"tables": [

    {

      "id": "18dd5480062-layer-2",

      "title": "Reated table",

      "url": "https://services9.arcgis.com/LMjydzYxR6YFiqk8/arcgis/rest/services/related_Layer/FeatureServer/3",

      "itemId": "50664ee6ac1745f5a13c1a6679459bf5"

    }

  ],

• Click on the save icon.
• Navigate to ArcGIS Online again and refresh the browser tab.
• Check the web scene, the related table is deleted. 

Steps to Reproduce