Welcome to the Magix Sound Forge community @Hitoshi-Takase.

"recorded at 12, 13" > Does this mean Sound Forge 12 or 13? What version of SF-14 " AS (Audio Studio) or Pro?
MP3 issues are somewhat common. There are two things your try prior to submitting a Magix support request.
Try resetting SF to the factory default settings, which also cleans the cache or uninstall with a third-party uninstaller which cleans the registry, then reinstall. Both of which have worked on for some other folks.

See these this recent threads:
https://www.magix.info/us/forum/soundforge-13-pro-cannot-read-save-mp3-format-files--1248180/
https://www.magix.info/us/forum/how-to-save-as-mp3-using-sf14--1251923/