The OCR1A sometimes fails to update in the simulator 2 display (at least with the mega168p). This appears to happen when the timer is in one of the fixed TOP PWM modes. When setting OCR1A when in one of these modes, the display shows no change, though reading from OCR1A returns the proper value.
Edit: This is in the 4.14 beta. I don't know if it happens in the current release version.