Interesting to hear more on the developments with Russia.
My theory is that Putin proved he was able to tip the balance in Syria, giving himself a seat at the negotiating table. Now he made his deal, he can no longer be trusted to help Syria.
The other possibility is that the whole thing is orchestrated from the beginning. Frankly, the way Trump is behaving, he's on board as well facilitating the fall of the US and the rise of the BRICS nations.