Hmmm... I gotta admit the timing of the token buy back is very fishy. If they wanted to buy back with imaginary tether usd a good time would be right before all the usd gets trapped inside the exchange (IIRC the token buy back happened days before the fiat stoppage).
The thing is the balance of their btc wallet was up about the same percentage since early march. So they might have just issued more tether usd because of the overall crypto bull run since then.
https://blockchain.info/charts/balance?address=3D2oetdNuZUqQHPJmcMDDHYoqkyNVsFk9r×pan=60days