Hi Guys,
I am now in a very delusive case. I simulated startup behavior from zero state and found that it shows oscillation with 10% less frequency, and could you help me understand that? when I performed stability simulation, it shows correct oscillation frequency as crystal specified. I also wanted to pss simulation, but always failed convergence. There are zero diagnal at output log file, but it's very difficult for me to find the root cause. Attached is startup sim results, when I magnified it, it shows wrong freqency sin waves. I simulated up to 2ms, and waves seems resonable stable, but still the wrong frequency as starttup very small sin frequency as attached.

Thanks very much.