Reproduction steps:
1. Open the attached project
2. In the Project window select the Sprite Atlas
3. In inspector switch the Max Texture Size to less than 1024
4. Pack Preview

Expected result: an error is thrown in console that indicates that the Sprite atlas needs to be at least 1024
Actual result: along with the size error, many MissingReferrenceException errors are thrown

Reproducible with: 2020.3.33f1
Not reproducible with: 2019.4.37f1, 2021.2.19f1, 2022.1.0b15, 2022.2.0a9

Tested on Windows 10

Notes:
1. Full error can be found in the report
2. The issue stops reproducing after a downgrade or an upgrade of the project and I was not able to reproduce the issue again by creating a new project. The project attached has the issue in it