The news about Knight going out of business is somewhat old. It was happened late Spring or early Summer. They still do warranty work and sell accessories. It is unclear whether they may resume production of muzzleloader in the future.
I doubt that lawsuits had anything to do with their closing down or suspending production. (If lawsuits were the reason, you would have expected Knight to file for Chapter 7 or Chapter 11 bankruptcy protection.). The rumors of lawsuits are associated with another inline manufacturer. I don't know if those rumors about that other manufacturer are true or not.
My sense is the Knight ran into trouble because of weak marketing and distribution. Plus, at Knight's price level, people preferred break action over the bolt. Combine these problems with a weak economy, and Knight probably figured that production of further muzzleloaders would lead to non-sales and losses.
That's my surmise of Knight's situation. I hope that they come back, because I think their muzzleloaders are very good quality.