the game would not show random friends who really are online, when the limit was higher. So it tends to bug the game if we have any more friends than this current limit.
a way to sort friends by last seen online would be a sufficient fix for me with the current amount of max friends, there are always people who come and go, but it's very tedious to check who is gone yet. so it takes some minutes before i can add a new friend and i've gotten used to how tedious it is, but sorting by last online would save a lot of time at least in this process, if it's technically impossible to have more friends in the game than the current maximum.
if there is an easy way to increase it without the game bugging, i'm totally for it needless to say.