Issue with `cluster`

Hi Mark,

I have seen that a similar issue has already been reported about the cluster function, but here you are an additional weird behavior I have detected so hopefully it can help you to identify the issue and solve it.

I have found it to happen in a very few occasions. But sometimes, whatever the reason, in the output of the cluster function we find replacements of some constructs by other ones. In this specific example, a complete branch is replaced, so we end up having 2 repeated branches (one of them with the reversed constructs).

Grid: Celia R.xlsx

Hope it helps. Thanks, again, José