Phone starts ringing mid convo, from person I'm talking to..

[SudoHacks]

Hey Folks,

Something I've noticed lately is that if I have been talking to someone for a little bit, usually around 15min, I will suddenly get an "anonymous is calling" message, and it's the same person that I'm already talking to. Whether I select accept or reject, I'll end up loosing the call and have to restart the freephoneline app and call the person back, which sometimes can take a good five min...

Any thoughts on this? Is there a 15min limit on call duration or something?

Thanks.