Stuck uart on devkit mango yellow dev RC7620 when use powered by battery

we use the yellow mango kit for dev rc7620. when we make the call, the receiver side rings and answers it seems rc7620 doesn’t return the connect signal as we want. this only happens when we power the kit with active battery. As for power from the micro usb cable to pc, it works normally. Why is there such a problem and how should we solve it when it comes to battery power?

is it duplicate issue as this one?

Yes, it issue
Thank you

Let’s go back to the original discussion thread then.