Thank you for the post.
To attempt to replicate this a new database file was created with 3 container fields and a single layout with 3 tabs. A different container field was placed on each tab. Each tab was visited in FileMaker Go 12.0.6 on iOS 6.0.1 and each container field tapped one after the other. The normal pop-up dialogue appeared after tapping on all 3 container fields.
Can you replicate this in a newly created sample file?
It may be a good idea to run a recover on your file to see if any problems are reported. Even if no problems are found, I'd test the recovered copy to see if it still exhibits the same behavior.
Things to keep in mind about Recover:
While Recover almost always detects and fully corrects any problems with your file...
1. The recovered copy may behave differently even if recover reports "no problems found".
2. Recover does not detect all problems
3. Recover doesn't always fix all problems correctly
4. Best Practice is to never put a recovered copy back into regular use or development. Instead, replace the damaged file with an undamaged back up copy if this is at all possible. You may have to save a clone of the back up copy and import all data from your recovered copy to get a working copy with the most up to date information possible.
If you are able to replicate this behavior outside of the current database file, using a new database file built in FileMaker Pro 12 or one of the starter solutions, please let me know.