Depends on your definition of 'manual'... a std K0x actuator can be moved by hand but takes fair bit of effort and leverage... if you can move it simply by fingertips then yeah something is wrong... however it should be noted that actuators are pressure fed and so shut by a spring. Springs do go soft but I have not heard of one breaking or going soft enough for easy movement... the diaphrams can split which means they won't open very well if at all when pressure is fed to them by the N75...
These items rarely go wrong tbh...
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