I have some custom boards using the MCF52254 which normally power up fine, but a recent batch is having a problem booting up frequently. I see that when it is not running that the crystal is dead. If I cycle the power quickly the crystal starts fine and the application boots normally. If I let it stay off for too long (more than ~10s) the clock doesn't start and it doesn't boot. The attached image shows the crystal circuit, which is based on the MCF52259 tower reference design.
I don't know of any changes between the last batch and this one, but they do apply a humiseal coating and I suspect it might be affecting the tuning. I've tried to remove the coating and I don't think it had much effect, but I'm not sure I got enough off.
Any thoughts on what I could try?