One day he tells you how great you're doing, the next day you're on the street.
It could be just that the manager was full of BS, or someone several levels above him or her told them to kick you to the curb and they couldn't say anything from the time they found out until the time they had to tell you.
I'm pretty certain that my manager was in the latter group.
I keep in touch with my old team. I haven't had the guts to ask if anyone's thinking about leaving, but they all say things are pretty crazy and the workload has increased due to the cuts to the team in Aug and delivery deadlines have not changed.
Managers are having to make excuses for poor performance by people who suddenly had to pick up tasks they didn't handle before and were not ready to handle now. In some cases, it's a shame that good people are getting tasks they have no background in and have to work to figure it out. In some cases, it's just poor work ethic and/or sheer incompetence. The sad thing is, the poor performance is now becoming the normal.
I'm glad to be gone. The new job has many of the same stresses. Upgrade this, rollout that, fix this other thing, and we need it all yesterday. But, at least the people here want to be here and enjoy their job. The toxicity of Cisco in general is infecting even the good teams that enjoyed what they did.