Hello @william.gadal.pro
I am not sure what the problem is.
What I can comment is that Bubble runs actions in parallel and not necessarily in order. For more info on this please review this post:
In order to ensure that an object is assigned to a desired user using the current interface that you kindly show … this should not be too difficult.
Perhaps a better look into the expressions and actions currently used could help to understand what is happening. 
