Did you ever solve this?
I’m having a related but slightly different issue. I’m using ACF in conjunction with the Events Manager plugin. If a user forgets to fill out one of the required Event fields, it prompts an error. When that happens, all of my ACF fields clear. It’s only the ACF fields — other fields are fine. It also only happens with ACF Pro, but not with ACF 4.x. The issue happens even with all other plugins deactivated and using the default WP theme.
