When charging while Mounted with a Reach Weapon such as a lance does the mount stop when you make your attack at the required 1 square away?
Most likely yes.
Except that with the updated mounted combat rules, both the rider and the mount charge.
If the charge doesn't land you in a square that allows for a charge, you can't perform the action. Mounted charge and reach no longer seem to work together.
The way I understood it was that the mount charges, not the rider. However the rider still gets both the benefits and penalties of charging and is allowed to make an attack additional to the attacks made by the mount.
So I'd say it doesn't stop 1 square away since the mount needs to be adjacent to the target to deliver its attack.
Be that as it may... assuming we're talking a horse occupying 2 squares, you can still deliver attacks with reach weapons since you're considered to be in any one of the two squares.
The rules are broken and do not work if you are riding a medium creature and wielding a reach weapon. In this case RAW the rider cannot make his reach attack (he would be forced to use it as an improvised weapon or make an unarmed attack) but the common sense approach would be to just allow his attack before the mount and I doubt any table, even PFS, wouldn't allow it this way..
On a large or larger creature the question is irrelevant, because attacks can be made from any square: thus, you can attack with a reach weapon just fine within 5ft by declaring the attack from the rear square.
The rider is in EVERY square that the mount is, not any square. they can't attack from the horses rear.
Except that with the updated mounted combat rules, both the rider and the mount charge.
The problem kind of existed before to.
Its a knight with a lance. He's charging, he's hitting. Any interpretation that doesn't allow that is going waaaay down the rabbit hole.
There's a thread out there on this, please go and hit FAQ so we can get an answer sooner. Because yeah, the rules as currently written don't work.