Database values disappearing

I’m using the toolbox plugin to resolve a expression with javascript and then record the resulting integer on bubble database, but most of the times this recorded value just disappears from the database with no reason, sometimes i do the same procedure and the result is recorded.

In my app some parameters are parsed through a popup and used to perform this calculation, and i can see on the back of the popup the repeating group getting updated with the correct value and the disappearing (the values are missing in the database too, not in the repeating group only).