While I'm not very familiar with the Icon, I have had some experience with the Encores. TC since being absorbed by S&W, has undoubtedly grown in sales. This isn't always a good thing in the beginning.
The encore barrels were button rifled, made one at a time, almost hand made. There have been issues with their barrels in the past, but Thompson took care of them at once. Now they have added much more complex design to their inventory, and may be having some toothing pains.
S&W offered a bolt action rifle in the past, actually a Howa in a different dress and they were excellent rifles. The Howa rifle barrels are heavy industry, hammer forged barrels, like Sako, FN, Mauser, Sig, ect. In Europe they consider button rifled barrels a Mom and Pop operation.
It would not surprise me to see Thompson, S&W go back to a major maker for barrels in the future, simply because at the increased volume of sales QC will be much more difficult. Manufacturing Button rifled barrels in volume would have to be a real headache, because of all the extra steps involved. Destressing, lapping, ect. None of these apply to a hammer forged barrel.
I own and have confidence in S&W products and believe they will iron out these problems, if for no other reason than to protect the product reputation.
I think Thompson may have tried to grow too much too fast, and are sweating over details that didn't apply to a smaller operation. All I can say is keep after them and try to talk to someone with real authority, that can authorize new parts.