After updating to 10 or one of the apps I haven't been able to use assistant while on a phone call. Previously I would set reminders or appointments during a phone call by using the home button to bring it up. It would mute the call and work as normal. After the update it will come up but the microphone stays active on the call instead of doing what I ask of it. Don't know if it's a hidden permission or just a bug. Any ideas?