To reproduce:
1. Open attached project ("case_1239007.zip")
2. Build and run WebGL build
3. Focus browser window and press 'a' keyboard button

Expected result: Cube object moves to the left
Actual result: Cube object doesn't move

Reproducible in: 2018.4.22f1, 2019.3.11f1, 2020.1.0b6, 2020.2.0a8

Reproducible in package versions: 0.2.1, 0.2.10, 1.0.0-preview.7
Could not test in package versions: 0.1.2, 0.2.0, 0.2.6, 0.2.8 (Due to errors in project)

Notes:
1. As a workaround keep checking 'Device'.current in Update() method until it's not null, then assign its value and use it
2. Browsers tested: Firefox 75.0 (64-bit), Google Chrome Version 81.0.4044.113 (Official Build) (64-bit)