Perhaps it can be can be made ambiguous in some context if you try hard enough, but that doesn't mean it commonly is so, or that it is here.
> I'm sure this isn't the best tutorial on the topic but it gives you a taste: https://www.barandbench.com/columns/shall-shocked-the-use-of...
Thanks, but the only thing that link gave me a taste for is terrible strawman arguments. (Or a severe lack of understanding of basic English.)
If you have "shall be" in a sentence, then that phrase is the verb of interest whose ambiguity (or lack thereof) you must examine, not the "shall" on its own. Claiming "shall" is ambiguous because it changes meaning when you put "be" after it makes no sense. It comes across as the kind of argument a first-grader would make.
They write: If the substitution rule is applied in the sentence: “The employee shall be reimbursed all expenses”, you would get: “The employee has a duty to be reimbursed all expenses”. This created ambiguity for the simple reason that the intent appeared to state an entitlement of the employee and not to impose a duty on the employee.
Do they lack common sense when reading this, or do they struggle with English? It's like claiming "I have a carrot" is somehow ambiguous because "I have been a carrot" means something entirely different. Does that sentence need disambiguation with "I possess a carrot" or "I have a carrot, but have not existed, as a carrot"? Are these serious arguments?