Putin has read the handwriting on the wall and he doesn't want to get caught up in a war with Turks, Saudis and UAE on one side and Iran and Assad on the other. Assad is far from secure.
There have been indications of new Russian pressure on the Assad government. Days before the cease-fire started, Mr. Assad dismissed it and declared that he was on the road to taking back all of Syria. But Russia’s envoy to the United Nations let it be known publicly that those remarks “do not chime” with Russia’s efforts. He told the Russian business newspaper Kommersant that Syria’s leaders should “take account” of Russia’s military help and follow its lead if they wanted to escape “with their dignity intact.”
In other word, time to leave while you can.