yes, doing what the previous poster did - giving vague "bad signals" even against company's policies - is what i consider immature and discriminatory.
references in form of background check - worked years a, b, c, on projects x, y,z - yes, sure.
references about performance, likability, etc - why ? how are you going to judge that ? are the references legit ? are you going to get references on the reference giving people ? are you gonna research the excompanies culture to judge tbe referential credibility ?
you're just fooling yourself giving any meaning to this, you could be as well tossing a coin.
wtf. what you are describing is something that i would say is suable. and should be.
you basically said dont hire that person to someone. because of your bad experience with that ex-colleague ?. you are denying that person a chance. how come ?
what are you going to do next time someone calls for reference ? the same ?
a) dont take these rejections personally. dont hold a grudge. it might be someone incompetent is reviewing your code. it might be the company does not have urgent need to hire but is only on tge lookout if they spot someone matching their (awkard) criteria.
b) if its a repeating thing consider asking someone (a friend, a forum, a senior dev) for review of one of these "exercises". this could show you what youre not seeing. or could show you your code is just fine or perfect and it's about the company not knowing what they want. so either you will learn something or you will boost your self confidence.
a series of "rejections" can put one's self-confidence to a test, remember good times will come again.
- the investors ? most likely they know your four man team is not capable of doing any solid AI work and are aware that your CEO is bullshi$$ing but they are actually betting on this ability to sell what does not exist being a personality quality.
- the customers ?
why should they care. if they care, they should ask where's the ai. "show me the ai"
- you ?
your not being fooled. you might have been when being signed up for the job, but now just accept it. if AI becomes a thing it might eventually find a way into your product. otherwise id just play along now while the cheques keep coming.