The answer lies in your question. Sometimes anything can happen. Generally markets are efficient, prices are stochastic and events are random.
Spreads are result of demand and supply, sometimes the historically observed spreads may deviate due to changes in demand and supply which in turn are result of various reasons like changes in expectations, corporate adjustments, awaiting for results or lawsuit actions or policy changes etc and many more.
If one can quantify the right reason quickly then there may be an arbitrage opportunity presented to act upon and profit and by doing so bringing the spreads to normal levels.