Mine seems to work fine
I have a Juicebox 40 purchased on Ebay as refurb from emotorwerks. I installed it myself and so far it is working fine. I have a friend though that had nothing but grief of the same sort where it just didn't charge some nights when it should have. I learned that after I had already purchased, but not yet installed, so was nervous.
I have mine set via the Juicebox app to only charge during my off peak times.
When I plug in at about 5:00 PM ,with the Bolt always set to immediate charging, the car does display an unable to charge message as I plug in, since the Juicebox is not willing at that time due to the schedule. But it does start at 11:00 pm as it is supposed to. So far so good