MLB The Show 21 was updated to version 1.12 by Sony San Diego Studio. You can find out the complete patch notes for this update from here.
The game is continuing to get post-launch support in the form of various fixes and updates. The latest one is for the Online Head to Head mode where the player could face a bug. It has been resolved now with this new patch. There are no hitting or gameplay balance changes implemented as part of this update while some misc adjustments were made as well.