Yes, I am getting to the point in which I start to call the WordPress core team members “idiots”, at least between me and myself.
Case in point is https://core.trac.wordpress.org/ticket/34689 which is about update_option not always saving values to the DB because it checks the value returned by get_option and performs the write to the DB only if that value is different than the one update_option is requested to save.
Actually sound very logical, right? If the values are the same, what is the point of wasting the resources to write to the DB. The problem is that the value that get_option returns is not the value stored in the DB as several filters might be applied to it, therefor in some situations the value returned by get_option might be the same to the one passed to update_option but still different then the one in the DB.
So why no one had noticed it so far? I think that most people are not aware that you can filter the result of get_option on the one side, and on the other most update_option are made in admin in which the filters mentioned before will not be set as they are useless on admin side.
It is surprising to discover such a bug in one of the lowest level functions WordPress has, a function being used by almost every plugin, but it is just shows that in software when you don’t know about bugs, it doesn’t mean there aren’t any and no matter how battle tried the software is.
What is annoying is the refusal of the core team to admit that it is a bug. In software development there are all kinds of situations in which bugs are results of bad design but once it becomes old enough it is hard to fix it because by then everybody expects it and therefor it becomes a feature. But when a = b do not make a==b true, there is just no way to pretend it is not a bug.