Steps to reproduce:
0. Switch platform to Android
1. Import the attached image (or any other square image) into a project
2. Set Texture Type to Sprite in Import Settings
3. Enable Use Crunch Compression
4. Enter some high value like 4096 in the field next to Compressor Quality
5. Hit Apply without clicking anywhere else
6. Compare the load time to the same action being performed with a number that is within the 0...100 range.

Note: I am attaching a user-submitted video. Testing it out on office computers resulted in a nearly negligible difference.

Expected result: the value doesn't get processed
Actual result: Unity seems to process the value if the user hits Apply while still in the field

Reproduced on: 5.6.4f1, 2017.0, 2018.1.0a4