Data shifted during Serial communication

Bassusour:
I just read it through, but there's nothing about data being shifted

Of course not. Because if you use that system it won't be shifted. Look at the technique in the third example.

You can send data in a compatible format with code like this

Serial.print('<'); // start marker
Serial.print(value1);
Serial.print(','); // comma separator
Serial.print(value2);
Serial.println('>'); // end marker

...R