When Select and Move brushes are used and after that when Flood Fill Brush is used, it makes the Tilemap to get erased. Refer attached video

Steps to repro:
1. Create a new project with 2D Template.
2. Hierarchy > Create > 2D Object > Tilemap
3. Window > 2D > Tile Palette
4. Create New Palette > drag and drop Sprite in the Tile Palette
5. Select Tile from Tile Palette and draw in Tilemap
6. Select tile in Grid and move using "Select" and "Move" brush
7. Select "Flood Fill" brush > select tile in Tilemap

Actual Result:
Tile gets erased while using the "Flood Fill" brush.

Expected Result:
Flood Fill brush fills tilemap gracefully.

Occurring on:
2020.2.0a10, 2020.1.0b8, 2019.3.12f1, 2019.2.13f1, 2019.1.11f1, 2018.4.14f1

Environment:
Windows 10 and macOS 10.14