The array is 16 analog inputs, till now these inputs are not connected to anything so they are random, except the first three elements of the array, connected to GND, in order to see the beginning of the array. The 2560 is continuously sending this array.
When using certain delay in the 2560 at each loop, it seems the array is received always correctly in ESP8266.
But with no delay, occasionally, the three zeros doesn't appear in the first 3 positions of the array, and are for example, in positions 7,8,9.
What is the explanation of this?