14 players from my local group just defeated Zapodos and did not get a chance to catch him. We all got kicked out after we defeated him. We spin to the pokestop , close app and tried again and clear cache. Each step was tried. What it did allow all of us to do was to battle again.
We did not have to use a new raid pass to try again but we all would error out when the timer went to zero to battle. For me personally this would be my 3rd raid boss that i did defeat and not receive rewards and a chance to catch the raid boss. My daughter has had is happen twice.
I email Niantic when it happen to my daughter and myself a week ago and well i was beyond upset when i get a response of hey we give out a free raid pass a day. I explain to them that i had purchase the raid passes for my daughter and myself but that was the email i received.
Tonight with 14 of us side to side expecting to enjoy the game but instead side by side we wrote to Niantic complaining about their game.