Ready.
This is the first figure of the second example at the end of the copycat82. It is the largest example, with a total of four figures. The section claims to be an example of mutual exclusion in distributed systems, and chooses an algorithm by Ricart (CACM, Jan1981, pp.9-17, "An Optimal Algorithm for Mutual Exclusion in Computer Networks").
The first observation about the figure is that it is exactly deadlocked. Each of the three components (transitions) C1, C2, C3, has three input places, and three output places, and only one of the input places holds a token (in each case). The intermediate component, comm, among them, has six input, and six output places, with no tokens. As a result, no component can fire. It is deadlock.
It appears, nobody, and no tools they use could spot this either.
Let's keep in mind also all the simplifying assumptions already claimed in the text, for this "largest example" in it: The underlying communication network be error-free, messages may not be delivered in order (that is, no handling in the part we find implemented), and that the nodes cannot fail.
And let me make one point clear again: The algorithm is cited from a CACM-published article, and it is not probably the source of errors. The errors are introduced in the very representation which is the subject matter of the copycat82.