Logic Pro X 10.3.1 -

: Time-based edits (cutting or inserting time) were updated to apply to inactive Track Alternatives , ensuring alignment across all versions of a track.

While 10.3 provided the visual and structural shifts, 10.3.1 focused on making those changes reliable: Logic Pro X 10.3.1

To understand 10.3.1, you have to look at the massive 10.3 update it stabilized: : Time-based edits (cutting or inserting time) were