sx127x configuration overrides LoRa mode when setting Standby mode

[RPadial]

I modified sx127x_set_pkt_type function in order to write 0x01 with 0x80 value (only set bit 7) when okt_type is SX127X_PKT_TYPE_LORA and int seems to change to LoRa mode. However, in the next configuration it sets Standby mode but it overrides LoRa mode.

Data: h01 | h00, h00 | h00,
Data: h01 | h00, h00 | h00,
Data: h81 | h00, h00 | h00, Sleep
Data: h01 | h00, h00 | h00,
Data: h81 | h00, h80 | h00, LoRa mode
Data: hC0 | h00, h00 | h00, h00 | h30,
Data: h86 | h00, hD9 | hD9, h06 | h13, h66 | h33,
Data: h09 | h00, h00 | h7E, h00 | h09,
Data: h4D | h00, h00 | h04,
Data: h89 | h00, h7E | h7E, h09 | h09,
Data: hCD | h00, h04 | h04,
Data: h1D | h00, h00 | h72, h00 | h70,
Data: h26 | h00, h00 | h04,
Data: h9D | h00, h72 | h72, hC0 | h70,
Data: hA6 | h00, h08 | h04,
Data: h31 | h00, h00 | hC3,
Data: hB1 | h00, h03 | hC3,
Data: hB7 | h00, h0A | h0A,
Data: h01 | h00, h00 | h80, Check radio is in LoRa mode
Data: h81 | h00, h01 | h80, For any reason library overrides LoRa mode in the next frame

I changed sx127x_status_t sx127x_set_op_mode to read SX127X_REG_COMMON_OP_MODE register before setting op_mode.

static sx127x_status_t sx127x_set_op_mode( sx127x_t* radio, const uint8_t op_mode )
{
sx127x_status_t status = SX127X_STATUS_OK;
uint8_t local_op_mode = 0;

if( sx127x_read_register( radio, SX127X_REG_COMMON_OP_MODE, &local_op_mode, 1 ) != SX127X_STATUS_OK )
{   
    status        = SX127X_STATUS_ERROR;
    return SX127X_STATUS_ERROR;
}

if( status == SX127X_STATUS_OK )
{
    local_op_mode = ( local_op_mode & SX127X_REG_COMMON_OP_MODE_MODE_MASK ) | op_mode;
    status        = sx127x_write_register( radio, SX127X_REG_COMMON_OP_MODE, &local_op_mode, 1 );
}
return status;

}