How to reproduce:
1. Open the user-submitted project ("BugReports.zip")
2. Open the "textureArrayBugs" scene and in the Hierarchy Window click on the "TextureArrayGenerator" object
3. Right-click on the "Generate Texture Array Bugs" script and click "Generate Texture Array"
4. Wait until the "textureArray" object is created and click on it in the Project Window
5. Observe the hang/excessive time for its Inspector View to finish loading
6. While the object is still selected try to select objects in the Hierarchy Window

Expected result: the time to view the generated object is 1-2 secs
Actual result: the time to fully view the generated object's inspector is way longer at 5-10 secs and any other action while the "textureArray" is selected is severely slowed

Reproduced in: 2019.3.0a3, 2019.2.0b3, 2019.2.0a12
Couldn't test with: 2019.2.a11, 2019.1.1f1, 2018.4.0f1 (The texture generation script breaks in these versions)

Additionally: Texture arrays with crunched compression textures cannot be generated at all and crash the Editor. To reproduce this right-click on the "Generate Texture Array Bugs" script and click "Generate Texture Array - Crash"