I found a fix.
Go to http://blog.elliotcondon.com/news/advanced-custom-fields-v3-beta/ and download at least v. 3.0.0 beta 2, then overwrite the files in your existing folder (/wp-content/plugins/advanced-custom-fields/), back up your existing files into a separate folder, and then overwrite the existing files on your server with the newly downloaded version.
Note: If you have paid for and downloaded Repeater fields and are currently using them on your site, the beta will fix previously known issues with fields disappearing, not being able to save data to posts, etc., *HOWEVER* any repeater data entered in the old system will no longer save to the database using the same methods, meaning it will no longer associate the data in the repeater fields with your posts.
For example, we have data associated with certain templates using the repeater fields on a new site. We couldn't change the fields in the repeater field because it would empty the existing data. Using the update, we fixed that issue, but then I had to export the database, find the old fields, and re-enter each of them on the associated pages.
A little bit of a hassle, but its fixed. Looking at the code, it looks like it should be a more permanent fix so we won't have to do this again in the future.