Moving into a Creature Space: AoO once (for movement) or twice (for entering square)?

[Garbage-Tier Waifu]

In a game yesterday, a situation came up where a Tiny creature tried to move into the space of another creature which had Combat Reflexes. The Tiny creature provoked an AoO from moving through the creature's threatened squares, but there was a bit of debate about whether moving into the creature's space was a part of the same movement that provoked an AoO for moving through threatened squares, or its own trigger for an AoO.

I allowed it to be only one AoO, but I want to get a rules clarification on this. How many AoO should have happened int this situation?

[James Risner]

Twice but only one AoO.

Basically one action provokes two ways. Eliminate one (such as 5 ft step) and you still have the other (entering.)

[CBDunkerson]

As written, it seems like there'd be two (one for moving OUT of one or more threatened squares plus one for moving IN to an occupied square), but there is a FAQ saying it is only one;

Tiny and smaller creatures: In the section on Tiny and smaller creatures, it says that entering a creature’s space provokes an attack of opportunity, but typically 5-foot steps don’t provoke an attack of opportunity. If a Tiny or smaller creature took a 5-foot step into a creature’s space, would it provoke an attack of opportunity?
Yes. Even with a 5-foot step, a Tiny or smaller creature entering a creature’s space provokes an attack of opportunity (unless it is using a more specific ability to avoid the attack of opportunity such as the Monkey Shine feat). This doesn’t mean that a Tiny or smaller creature entering a creature’s space and moving out of a threatened square with a move action provokes two attacks of opportunity from that creature, for the same reason that moving out of multiple of a creature’s threatened squares in the same move action doesn’t provoke two attacks of opportunity.

[Garbage-Tier Waifu]

Ah, okay! Thanks very much for the clarification. Im glad I ended up ruling the right way and didn't accidentally screw my players over.

[Firebug]

With entering the occupied square part, which square is the tiny critter in when the attack of opportunity is resolved?
This is important for larger enemies with grab if they can stop you outside their square.

[CBDunkerson]

AoOs are resolved before the action which triggers them... so the creature would still be outside the enemy's space.