I'd second the option to dig and move the fans; that always works for me, too. I haven't noticed any bugs, and deformed fans are always seen right next to lots of others that don't twist around at all. With that in mind, one might ponder the interesting array of their dis-ease, and wonder why its always just connected to particular fans (were it insects, you'd usually find more than one infestation). Certainly, it could be that just one cultivar is susceptible to a mite, but it would have to be quite an interesting round-robin feast the insects held for the sickness to rotate in turn to new cultivars each year, and some rhyme or reason for why they vacate the re-planted ones and don't return, as it happens.
On the other hand, for anyone who manages to get by with little or no insecticides, it may be worth trying to break up the clump first and/or move them to another location. I have a small twisting clump that I can see has sent roots rather wildly "tossed upward" and back down through a tangled web of neighboring root systems, so I'll be digging again, setting aright, and watching over them this week. Like others before this, I have no doubt the cultivar will recover its health and uprightness as it settles into its better situated new home, and be blooming next year when yet some other fan or clump goes out of whack.
Hoping yours might do the same if you give it a try. Might be worth it to work each solution on a different section of a clump to see what works out best for a healthy garden in the long run.
