The notion of a broken clock being sometimes right is based on a gross misunderstanding of what information is.
A clock that always shows the same time is never right, even in the moments of the day when the time happens to be what it shows, because you don't gain any information about what time it is by looking at the clock.
This reasoning also applies to chatbots. If you can't tell whether what you have been given is useful information unless you alreay know the information, then you haven't been given useful information.
It seems like the step of error checking has been missed off and left to the user. It’s as if you sent the time as beeps down a really noisy phone line - you’d need some form of checkbit for each package of information to have any assurance of veracity. We do this with people automatically - if someone tells you something, you’ll place less weight on it being right if that person also says verifiably false things. You might ask more questions to check against known info.