why the ctrb and obsv is not full in Modal Analysis of a Flexible Flying Wing Aircraft

here is example link

Modal Analysis of a Flexible Flying Wing Aircraft - MATLAB & Simulink (mathworks.com)

i know if the actuator can excite all mode, the system is ctrb and if the sensor can measure all mode, the system is obsv

this is bode plot of state space equation.

i thought from this bode plot. the sensor detect mode between 6Hz~35Hz and the actuator can excite the all of mode between 6Hz~35Hz

but the state space of the outcome of example is have 24 rank but the ctrb and obsv is just 5 rank.

why this is happend? because of unstable mode? what is unstable mode? or because of the algorithms?

please give me your knowledge