addendum:
So, i removed the length check on that receiver, and the serial console on the receiver shows: 14378
¿WTF?, where does that number came from
Another test:
If i move the "uint16_t data;" declaration to global instead of inside the loop, the receiver now shows 0
I changed the transmit sketch back to the default one, and now the receiver shows "25960".
edit 2:
Change the transmit value to "512", guess what?, receiver still shows 14378 being received