When a mosaic property is unchecked in the Sprite Import settings and the changes are applied to the sprites then ArgumentException appears in the console,refer attached video and .PSB file

Steps to Reproduce:
1. Create a New Project with 2D Template
2. Import .PSB file in the project.
3. Project > Fei_Cel_group.psb > Insprctor > Uncheck mosaic > Apply

Actual Result:
ArgumentException on applying Sprite Import settings with mosaic property unchecked

Expected Result:
Sprite import setting is applied to the sprite without errors despite mosaic property checked or unchecked

Reproducible on:
2020.2.0a14, 2020.2.0a12.

Working fine on:
2020.2.0a11,2020.1.0b12, 2019.3.15f1

Package Found version: 3.1.4, 3.1.3

Environment:
Windows 10 and macOS 10.15