I just realized: Banks and hotel companies typically have contracts which each other.

I wouldn't be surprised if it's a many-month or many-year job for oodles of lawyers to determine if the contract they US Bank with pre-split Radisson Rewards is still valid and to what degree, given the upheaval of the hotel company the contract was with. Whatever problems we individual travelers may have with the bank or with the hotel company (companies) may be dwarfed by the mess made of any contracts between the two that people behind the scenes may be working 24/7 to figure out!

So front-line workers at the bank that you talk to may not have the latest information about what's going on behind the scenes with all the contract lawyers, until the contract is resolved one way or another. But the lawyers presumably told the bank not to take any more applications for any of these cards until the contract is all sorted out.