Anders_ASUSHi... Regarding vibrate when answered issue, if we enable touch vibration option in sound settings menu, then the vibration when answered option works for all the answered call in both the SIM card.
Could be a bug but first I need to ask if you tried calling another phone that you have so you know when the call is answered? The vibration is quite subtle and easy to miss. If this is the case, then I can ask if we can make it longer.