I’m sure the holidays have been slowing things down, but I thought I’d just report back.
SimCoders have had a look at this issue and came up with a solution in their software, and the fluttering is now gone.
Read more about the exchange here, and do the simple fix if you also have this problem:
BTW: I tried using the Thrustmaster TPR pedals while this issue was resolved. They are fantastic pedals, but after using the Brunners for a few days before… oh well… no comparison. I thought force feedback rudders were unnecessary. I was wrong… 😀