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The other answers already tell you what went wrong, but I will add a terminology note: the term for what is happening is that the pencil $A - \lambda B$ is a singular matrix pencil, i.e., $\det (A - \lambda B)$ is identically equal to zero. So there are no generalized eigenvalues (or, at least, they cannot be defined as usual as the roots of the generalized ...
I suspect the root of your trouble is what has been detected in the comments by Vibe: For any number $\omega\in \mathbb{K}$ (with $\mathbb{K}= \mathbb{R}$ or $\mathbb{C}$) you can find $\boldsymbol{X}$ such that $AX = \omega BX$ (with $A$ and $B$ taken in your concrete example). You have already decomposed the problem in 4 blocks of 3 variables. Then let us ...