Pitot-failure
On ground low power is applied to the probes.
(at least one engine operating)
In flight it changes to high.
Probe caution light can be a spurious failure+
can sometimes be reset.
Companys like Goodrich,Thales or Gsis are manufacturing probes.
All of them can fail (heating elements).
Has nothing to to with FBW.
In recent years two 757 are crashed, due to airspeed
failure, caused by the same problem.