We have now had five of these devices require recovery.
Acer says they support the hardware and Google supports the OS.
Google says they support the OS if you buy the management (we did not)
Otherwise you are left with online forums for support.
In our case recover seems to have solved the issue with both Acer and Google says points to a software issue not a hardware one.
Recovery (if you are prepared for it) could take as little as 5m per device.
Each of them fails to boot, but works fine after the recovery process.