Hi. In-game servers list is just an extra list added to this network 1,5 year ago.
Main, 3 years old list is on
http://crymp.net/master.php - you can use it checking www or entering console "~" directly in game and typing "serv".
That second one in-game type (classic one) doesn't depend on us but is based on OpenSpy free service. There can be errors like this because of that, things like: servers disappearing from the list, no refreshing of player names, and so on (not often but can happen few times in a month) - this is why you always should use classic in-game servers list only as an additional one. It is possible that it's gonna change in the future and we will be able to run our own in-game servers list along with www and console type lists so there won't be any errors there.
But right now....
...Please remember that main list which you can rely on in 100% is the list shown in console or on our website - it will always show you the true, full settings and real status of each official server. Good luck.