How to reproduce:
1. Open Unity
2. Open 'Tile Palette' window
3. Create two tiles using a sprite(or sprites)
4. Save project
5. Enter edit mode and move one tile.
6. Save project
7. Disable tile palette edit mode
8. Reload project(If no unexpected result detected)

Expected result: Tile appears in a new position
Actual result: Tile moves back to old position after saving the project

Reproducible with - 2017.2.0b7, 2017.2.0f3, 2017.3.0a4, 2017.3.0b2
Not reproducible with - 2017.2.0b4, 2017.2.0b6, 2017.2.0p1, 2017.2.0p4, 2017.3.0a1, 2017.3.0a3, 2017.3.0b3, 2017.3.0b11, 2018.1.0a1, 2018.1.0a7
Could not test:
5.6, 2017.1
2017.2.0a1, 2017.2.0b3
(Tile Palette has not been introduced yet)