Strange bug with timer and oneshot

Intent was to vary the timer so the first time at turn-on, it only does a short mute, and then for a fault during normal operation, it does a much longer mute.  So I made this circuit, and it behaves bizarrely.  On turn-on, the OneShot timer rises to 1 after the 2 second delay, even though the Timer output that's driving it doesn't rise to 1 until the 10 second delay.  The OneShot is predicting the future?

After turn-on, the OneShot stays forever on, and switching the switch causes the Timer to change after a 10 second delay, which is as expected.

So I think it's a bug?  I'll try to find another way to implement the desired function