It seems to me that this bug has been around for quite a long time.
In general, you do an update in the 3D with a right-click on the welded parts folder, then in the 2D if there is no update after a CTRL+Q, you have to delete and then reinsert the table...
There is therefore no automatic update of the welded part list from a drawing template file for a new mechanically welded part. Maybe in a future version of SW?
The "automatic update" checkmark when you right-click on the list of welded parts means that you don't have to create the folders that group the different bodies in the 3D model yourself. In case of adding a new body, Solidworks automatically creates a new folder when you click on "update", then by pressing CTRL+Q in the drawing, the list of welded parts is updated.