Well, it's a comma-splice (joining two independent clauses with a comma). There's room for debate about whether all comma-splices are run-ons. There is also room for debate about whether all comma-splices are style errors (Strunk & White advise against them, but they give a lot of bad advice).

I think, however, that neither of these changes are unarguably fixes for incorrect grammar. See http://motivatedgrammar.wordpress.com/2012/07/23/comma-splices-historical-and-informal-not-wrong/ just for an example argument that the comma-splice is not ungrammatical and may not even be the wrong choice stylistically.

The 'was' in the other changed sentence isn't necessarily ungrammatical either, although in that case I agree that 'is' or 'has not been' would be a stylistic improvement.