Errata на m8:
2. Interrupts may be lost when writing the timer registers in the asynchronous timer. If one of the timer registers which is synchronized to the asynchronous timer2 clock is written in the cycle before a overflow interrupt occurs, the interrupt may be lost.
Problem Fix/Workaround. Always check that the Timer2 Timer/Counter register, TCNT2, does not have the
value 0xFF before writing the Timer2 Control Register, TCCR2, or Output Compare