Mutate data before saving to a pivot table

[OvalMedia]

I have 3 tables: client, contact and client_contact, client_contact being a pivot table.
Alongside the ids of client and contact it should save additional data like the current user's id.

But I can't figure out how.

In the ContactRelationManager the table function looks like this:

public static function table(Table $table): Table
{
	return $table
		->columns([
			...
		])
		->filters([
			//
		])
		->headerActions([
			Tables\Actions\CreateAction::make()
				->mutateFormDataUsing(function (array $data): array {
					$data['user_id'] = auth()->id();
					return $data;
				})                

		])
	;
}   

I figured mutateFormDataUsing would do the trick but it doesn't. Is there another (similar) function for this purpose?

[danharrin]

Ensure that user_id is defined in the withPivot() method of the relationship