Issue with shop associations

Setup this configuration:

1) Multishop install with 2 shops: A & B
2) Create category CAT_A and assign to both shops, A & B
3) Create product PROD_1 and assign it to CAT_A only on shop A
4) Create product PROD_2 and assign it to CAT_A only on shop B

Now with "All shops" selected in the dropdown:
5) Make sure quick edition in grid is enabled
6) Click on CAT_A category, so on the product grid you see both products PROD_1 and PROD_2
7) Change product name in grid of PROD_1 to, for instance, PROD_1changed
8) Now you will see that, incorrectly, the product is associated to shop B (remember it was only associated to shop A)

This is a big problem for me, because I share categories between 8 shops, but some shops have products that must not show in other shops in those shared categories. But sometimes I do have to change the name of a product "in all the shops it is associated to" and now this is not possible in the Store Manager because it incorrectly associates the product to all shops.

I have tried this same change in the back office and the issue does not exist. If you edit a product - with "All shops" selected in dropdown - that is associated to Shop A only and click "Save" the product remains associated only to shop A, which is the correct behaviour.

I believe the shop association of a product should NOT be changed by any modification done on the grid. It should ONLY be changed when the shop associations are specifically modified in the lower tab under the grid for this purpose.