Greed and stupidity, it looks like. Possibly it's a New Coke gambit of some kind..?
They say sourcing/supply chain issues, but other brands say they haven't had any such problems.

The other brands sell theirs for a lot more than Twinings did.

If it's a New Coke thing, expect the original flavour to return but at 5 times the original price.
( brb Monkhouse Stampede, Mon 1 May 2023, 16:27, archived)