strange, i'm reading that the chromebook 3 is updated past android 4.1 which is the base requirement for FF android, so I'm unsure why this is happening. Logging it as a bug for now, unfortunately there isn't much we can do until it gets looked at :(

Thanks Eve, One thing I should mention here is that this is a Chromebook enrolled in a G Suite domain. But, we have had a look through the policies and can't find any issues with what's configured there. I've been testing on my own Chromebook (Acer model) and havne't been able to reproduce.

Any logs we could retrieve that might help the troubleshooting?

Update your google play service and clear play store cache and data and retry to install the Firefox.