[Discuss-gnuradio] xlating filter will introduce phase shift

I use xlating filter to down convert signal. after I down convert signal it I decode it.
however the data decoded is still the signal in 0 frequency before down convert.
I check the xlating filter code it will change the signal phase to avoid aliasing, yeah
it avoid aliasing but it is not the data I want how can I recover the data's phase after
xlating filter?

Regards!