@gulliBell
What does the condition of the hydraulic fluid have to do with the 12th August accident?.....The hydraulic filter on the downstream side of the servo is a bypass type, but that is for a different reason (you don't want that filter blocking because the pressure across the servo will equalise causing the piston to lock).
My focus is not like yours. The issue of the Servo Actuator's is not related to filters or filter’s bypass. The issue is the Servo Actuator design. When the Servo Actuator's and its spool valve's C3 return port or both of the ports are blocked. If this will happen then the Servo Actuator will be jammed or fully extended. This will cause that the helicopter will come immediately unflyable and no single caution is addressed to the crew. If the blockage is partial or temporary then the situation could be that the controllability has been lost temporarily.
Let's wait until that we have more precise information like FDR data of 12th August, 2015 accident or when we have information of the fluid contamination or non-contamination.