Snap Mode: 1/32 Triplet (1/48)

Set the Snap Mode to a 1/32 triplet (i.e. 1/48 of a bar).

The snap values are found in the Snap menu displayed in the Piano Roll editor.

Snap to grid in the Piano Roll Editor in Logic Pro — Apple Support

The Piano Roll Editor has a grid, similar to the Tracks area grid. When Show Advanced Tools is selected in the Advanced preferences pane, you can set the Snap value for the Piano Roll grid, independent from the Snap value for the Tracks area grid. The Piano Roll Editor Snap pop-up menu contains additional values including specific note values.