I use to have a nice thin montell that had a water crystal formed (encased) in the flint until it magically fell out one day leaving a round hole through the point very similar to this one. It might explain this one, as the hole certainly does not look drilled or intentionally made in any way. Flint & chert are silica mineraloids (ancient sea life) that was deposited on the sea bed in clay sediment then (limestone now) in unconformed beds/layers. There can be alot of impurities in these materials.