I have just repaired some wall in my house, I put in some iron pillars to reinforce the roof?

between the pillars blocks were used to build a new wall. Now that the painter is painting them after plastering I can see the traces of the Iron pillars coming through & little specks of what appears to me as rust coming through the paint afrtr two coats of paint The metal bars were given a coat of anti rust before the wall was built Do you think if it gete another coat of paint the problem will be fixed or what is the Solution to leaving the wall looking all the same