Crystal is not a third overtone type is it. If so try fundimental type this
may resolve the problem. Or could the value of bypass capacitors be marginal
check device data sheets for correct window of values Or use disamilar values
for bypass capacitors Or use ceramic resanator with inbuilt bypass capacitors
Or add series resistor 500R or so with the crystal.

Cant think of any more off hand but I am sure others will

Cheers Steve.....