Hi
This behaviour is really strange and I never really seen before
You can use the phone without the brackets but it isn’t recommended as if the device is dropped it can unplug and prevent the device from working properly
I would try cleaning the connectors on the device and the parts with isopropyl alcohol to see if it’s caused by dirt being in the way of making a proper contact
Hopefully this helps, if it doesn’t give me a shout
Thanks:-)