I have found a small bug in product's sons display: I made a product son and assigned it to a registered user group.
And I have found that the son direct link correctly gives back a "non existent product" error message, but the son's name/sku still appears in the dropdown sons list.
To reproduce the problem, simply make a product, a son, and assign the last one to a registered group.
Not a big problem, but it's seems to be wrong anyway :)
VM 3.0.8 - J 3.4.1