By Laura Davison From Bloomberg News WASHINGTON—The Internal Revenue Service is under pressure from a large group of lawmakers to stop penalties and pause automated collections from taxpayers whose returns have been caught in a processing backlog. In a letter signed by at least 216 Republicans and Democrats from both the House and Senate, the legislators urged the IRS to streamline the processes for resolving penalty-abatement issues and amended tax returns. They also asked for a halt in automated collections until the agency could work through some of the backlog and give relief to taxpayers who had already paid at least 70 percent of their taxes. The IRS had more than 10 million unprocessed tax forms as of December, according to the letter, led by Senators Robert Menendez, a New Jersey Democrat, and Bill Cassidy, a Louisiana Republican. The IRS has said it generally starts a tax season with fewer …