Weird google voice issue

After the update, stock or custom rom i cant answer some calls from google voice by pressing 1.

Here is some background on the issue.

I have it setup for call screening so it says "call from ...." when i pick up the phone. And i have to press 1 for answer and 2 to send to voice mail.

Some calls i press 1 and it works fine no problems.
Other times i press 1 and it just does nothing and i end up missing the call when i wanted to answer. Now it registers as me pressing one it makes the beep and it shows up on the screen but it doesn't answer the call.

I uninstalled flex dialer and it happens when stock (sbf) or custom roms. i only noticed it after the baseband update. it seem to work fine before then.

To fix it i just turned call screening off but has anyone else seen this?