I am a newbie with OOMA and I tried to avoid having to press 1 when forwarding calls to my T-Mobile lines. "Require Key Press on Answer" being unchecked was not enough to make this happen. I still had to press 1 for incoming calls. While on the line with a second tier support person, and it still not working as expected, I had an idea between test incoming calls to turn off "Ring Home Phone". Only then does it answer on my (and my wife's) cell phone for each of our respective lines without the key press. It looks like a software glitch.
I asked the support person to escalate the issue so that hopefully this can be rectified. If there is a work around that someone is aware of, I"m all ears.
BTW, my landline phones are Ooma HD3 phones, if that may be contributing to the issue???