Bank of America Corp. is suing its mortgage insurance company for denying its claims. It’s the latest twist in finger-pointing over the mortgage crisis. The bank says that Old Republic Insurance Co., which Bank of America paid to insure it against losses on potential borrower defaults, is “manufacturing excuses” to deny the bank’s claims. In a lawsuit filed last week in district court in Charlotte, it calls Old Republic’s conduct “aggravating and outrageous,” and says Old Republic is making “unreasonable interpretations” of the requirements in its policies.