I have two of their MagGo packs from Costco. I did have an issue out of the gate, but found it was a “magsafe case” I was using was designed way out of spec for any wireless charger to work correctly. Other than with the one case, these work perfectly.
Sounds like it’s maybe defective. I don’t have that one specifically but I have several of their chargers and power banks and I’ve never had issues with them.
Can’t answer your question exactly, but I can speak to MagSafe chargers generally if that helps. I have an older (now discontinued) Apple MagSafe battery pack and it works just fine. Doesn’t disconnect at all. It charges maybe a smidge slow but not really noticeable.