Fixed in 1.8 Beta 4.

The problem was the code that restored the default event handler to a ship when setting it to Nil. The ship broker code was setting the default handler to Nil to turn the ship into a "generic" ship.

I need to rethink how wingmen are implemented. They should probably use generic ship classes (with no default event handler), which get specific wingman event handlers. Until then, these "special ship classes" will not go back on sale.