Biped Misbehaving: cannot set a free key


I’m on frame 607 of an animation (yeah, it’s a long, 28-second, continuous shot) and suddenly the Biped I’m using to animate the character refuses to set a free key on hands and arms (fingers are a separate track because they have to be; they’re all set to free keys, though).

If I manually set a key past 607, it turns orange. If I set a key after that, it will be yellow.
It doesn’t matter what I press; whether it’s manually setting a key of a specific type or just using auto-key. And I’ve checked; the anchors are not on.

If I try to move the arm by grabbing the hand and moving it, it’ll snap back to where it was as soon as I let go of the mouse button. And no key will be set.
Rotating seems to work fine, however…though that’s an awfully clunky way to get a hand in the correct position.

Pasting a posture does nothing. Like, literally nothing.
…sometimes. Sometimes it pastes…something. But it certainly wasn’t the posture I’d copied before!

Copying/pasting free keyframes from before 607 to past 607 will no-crap-at-all change from being free keys into the orange-then-yellow I described above!

I have no idea what in Hades is going on, but I could really use some help; I am so close to rendering this bad boy! Thanks.


I just tried it, and moving keys around on the timeline changes what type they are. Seriously.

The keys were orange, yellow, yellow, then black, oddly. Grab the black one on the timeline and move it to before that second yellow and suddenly the yellow becomes black and the black becomes yellow. Move any key to before the orange one and it becomes orange, the orange becomes yellow, one yellow stays the same, and the second yellow becomes black.

What. The. @#$%???