What is going on with our alder tree?

We have a youngish (5-10 years old, 15-20 feet high ) Alder tree that was doing wonderfully until this year - loving our rather damp garden. This summer it suffered from a large attack of what I think was alder beetle larvae and adults - losing a high proportion of leaves.  Now something very odd is happening to the cones.  They are sprouting on the tree (this is late August) and the resulting shoots are twisted and dying. I cannot find any reference to this.  Has anyone got any idea what is going on, does it matter, and, if so, what we can do about it?