Probably there's nothing to make of it but there's been no announcement that Acting Social Security Commissioner Carolyn Colvin is resigning. There had been several reports that she was not planning to stay in her job into the next administration. It's only two weeks to inauguration day. If she has already resigned effective on some day in the future, I would expect an announcements from Social Security and a press release from the White House thanking her for her service.
Colvin's term as Deputy Commissioner of Social Security ended some time ago but the law allows her to continue in office until a successor is confirmed. She can also stay as Acting Commissioner until a new Commissioner is confirmed unless the new President designates someone else to be Acting Commissioner.