Troubles on serial port with Uno wifi rev2

Hardware Arduino WiFi Rev2
6

The Arduino megaAVR Boards core does have its own SoftwareSerial library:

I just did a quick test with this sketch:

#include <SoftwareSerial.h>
SoftwareSerial softSer(10, 11);

void setup() {
  Serial.begin(9600);
  softSer.begin(9600);
  delay(1000);
  Serial.println("Hello World");
  softSer.println("Hello World");
}

void loop() {
  if (softSer.available()) {
    Serial.write(softSer.read());
  }

  if (Serial.available()) {
    softSer.write(Serial.read());
  }
}

What I found is that, consistently, the first thing sent from the software serial port is corrupted. After that it works fine. It seems like maybe there is a bug in the Arduino megaAVR Boards SoftwareSerial library. However, it's not a complete loss. A workaround would be to make a "sacrificial" initial print to the software serial port before any print that is essential. That assumes the corrupted "sacrificial" print will be ignored by your fingerprint reader.

Of course using Serial1 if possible is ideal, since hardware serial is always better that software serial when you have a spare hardware serial port.