(i know it is not recommended but in this instance it work better than child records)
Sorry, but I have my doubts about that...
You've encountered a known bug in FMP 14.
For More Information see: FM14 Client drops repetitions
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip