It is my understanding you are correct. Until 10k, merger is not complete. Therefore we trade as normal under new symbol. I really feel Rufus should have done a share count with DTC and announced it with the current Cusip change. I doubt that is going on behind the scene, but would force the shorts to cover.
I don't know if a 10K major news announcement of a merger can allow them to halt the stock and reprice or not? That is a department in my 6 years of trading I am not sure of.