This is a great question because it challenges generally accepted principles of prop torque *generated by a piston engine*.  One clue in the question states "a twisting moment creating by the turbine", and there were thoughts of the slender pylons on jets: is there a torque stress **on the motor mounts?**.

Certainly a twisting stress on the turbine shift, whether it is run through a transmission or not.  So let's load the prop while the jet is running.  Notice that blades are *symmetrically arranged around the shaft* compared with pistons pushing one at a time *away from the center of rotation*.

The *symmetrical* push on *all the turbine blades* by the jet exhaust gasses does not produce a torque force on the mounts, only a torsional stress on the shaft.  The *symmetrical* drag load of the *prop blades* does not produce a torque force on the mounts, only a torsional stress on the shaft.

One may surmise that *if the turbine torque and the prop load torque are balanced around the center of rotation, there is no torque on the motor mount*.

However, if one component comes out of balance (such as the prop), the motor mount may be easily torn off.