it's probably on our side, but if it's the normal forum sort order, that's just kind of the way that is right now, and the code that does that is stupidly ugly (it's ugly and it doesn't have to be, but unwrapping spaghetti is harder than cooking noodles properly from the outset).
if it's the tapatalk module, then we have some control over it; we don't usually touch the tapatalk distributions, though, and due to some other large changes we've been rolling into the code i'm hesitant to customize anything about a tapatalk module right now.