A hotfix is currently rolling out. Here are the patch notes:
Issues addressed:
[list]
[*] Fixed: The addition of SP/RP pitcher roles not taken into account when importing teams from SMB2
[*] Fixed: Potential crash when trait was activated at the same time as a substitution occurred
[*] Fixed: 'Star Studded Offense' achievement not unlocking
[*] Fixed: Bat and Starpoints sounds
[*] Fixed: Framerate stuttering and/or framerate deteriorating over the course of a game
[*] Fixed: Windowed/fullscreen switch not working correctly
[*] Fixed: Incorrect statistics gathered in online co-op Franchise/Season/Elimination games
[*] Fixed: Potential server crash when a forced pitcher substitution was left to expire by the player
[/list]