Sounds like something that may possibly pop up with a wheel speed sensor problem. This is not something an OBD-II reader can catch and may require the use of a Subaru proprietary scan tool, usually only found at Subaru dealerships and Subaru-specific shops that can afford the scan tool.
The owner's manual lines out all potential issues or behaviors of those malfunction indicator lamps in page 3-12 (Check Engine light), page 3-19 (VDC light), and 3-22 (Cruise Control light).
Based on the descriptions, it would be best to bring it to a local Subaru dealer for further diagnosis. It would be best to tell the service advisor with as much detail and conditions as possible so they can best pinpoint the problem. A wheel speed sensor or other problem related to those subsystems may become a serious safety in the long run.