Reproduction steps:
1. Open the attached project named "Case_1148573"
2. Open the Sample Scene and select the Tilemap gameObject
3. Observe the Tilemap's collider

Expected result: Tile's collider matches the grid ( Snapshot_1148573_V1 )
Actual result: Tile's collider is offset on the X-axis ( Snapshot_1148573_V2 )

Reproducible with: 2019.1.0a1, 2019.1.0f2, 2019.2.0a13
Not reproducible with: 2018.3.14f1
Could not test with: 2017.4

Notes:
1. Isometric Tilemap was not available in 2017.4
2. Tile's Collider Type is set to "Grid"