Does your machine have a vibratory or rotary pump? If its the part Im thinking of, that looks like the overpressure valve (OPV). I know that vibratory pump machines have an OPV in that location, but Im not sure what rotary machines use to regulate the pressure.
It is perfectly normal for the OPV to release water in to the drip tray when under pressure during a shot. This is how the machine regulates the brew pressure - excess water pressure is released in to the water tray.
This is the part (OPV) on my Faema (internally identical to Cimbali Jr). Looks a little different to the part in your photo though.