I've had a problem for several days now (I've heard some people say that they encounter it after killing the Mirelurk queen at the Castle. I can't say for certain that this triggered it for me, but I didn't start noticing it until after I finished that encounter).

All of my NPC companions are obsessed with mirelurks. They no longer talk about anything else when not in my company. Often they'll simultaneously blurt out their various mirelurk lines -- which creates an odd cacophany of bellowing super mutant, world-weary detective, Irish accent, and smarmy English butler.

I have learned everything there is to know about mirelurks. Couldn't they be patched to talk about something else annoying incessantly, like, say, Red Sox baseball?

We live in interesting times...