Update of a static table

Hi eveyone,

I have a table (call it table C) tha is a combine from a relatively big table of non changing historical values (table A) and a far more lean table of current values (table B)

To get rid on the useless udpate of Table A I have deselected these two checks:

None the less the combined table (Table C) still updates the rows corresponding to table A taking a lot of time to complete the update

How can I solve this?

Thank you in advance