Dwillight is a test island, yes? Test implies not only that there will be bugs, but when you play on a test server, you then become a tester. Unless he manipulated code, or knew this bug would occur in the first place (as in prior to the moment he became lord of a region no longer apart of his realm), he cannot be blamed.
Correct me if I have the wording wrong on the official rules but "Deliberate" is the key word in this violation.
Deliberate: "carefully weighed or considered"
He saw an option that shouldn't have been there and when presented with the opportunity to "test" it, he did. This all happened over a course of one or two days. To my knowledge, there is no way to prove that he knew the true consequences or had the time to considered them carefully.
The IC gain as a result of the bug was Morton becoming a Lord again.
The closing of RCs and duchy transfer were not bugs. Any Lord of a region has the right to do this. Unless you can prove, his testing of the buggy voting system was a deliberate attempt to have the ability to close RCs and transfer the duchy back, there is no case.
You cannot prove that Morton putting his name in for the Lordship of the region was exploitative. For all he knew, the voting could have been canceled before it was carried out.
His motives are purely speculative. There is no way he could have carefully considered this action before taking it and therefore it is not a deliberate use of a bug for IC gain.
