DA14580 UART, strange behavior

Dear all,

maybe it's all normal, since i am quite new to BT and dialog chips.
A board i am working on has DA14580, it has been wired to be controlled
trough UART.
But, immediately after the board boot, i see with oscilloscope a strange BT
chip traffic on both UART TX and RX, like some continuous burst of data.

Is it possible the module is bootstrapping in a non-UART mode ?

Eveyr help is appreciated.
Angelo