nRF52832 - issue with BLE UART (NUS)

[armtech]

Hi,
I'm using two nrf52832 boards to communicate via BLE UART with smartphone.
For firmware building is used Arduino 1.8.18 + Nordic nRF5 Boards 0.7.0 + BLEPeripheral last version + serial example.
Strange thing is that one board successfully supports data exchange with a smartphone, the other can only connect, but cannot exchange data.
The one board nRF52 DK is succes works (used as a programmer), and other is custom board have issues.
Both boards have same IC nRF52832-QFAAE0.

Could it be that this issue is related to chip revision or Softdevice version or circuit?