I am facing the same problem, did you find any resulution for this?

I had the same problem. If you are still stuck with the problem: The following video helped me: https://www.youtube.com/watch?v=IXdiRmcNj-o

Hey Gerald, in case you have not fix the issue. Just so you know Reference qualifiers like this are created on the platform and then the mobile app builder will obtain this behaviour automatically. However, if you use an Action Item that is of type "Script" it will lose the behaviour unless you tick into "use current record as condition" so that should fix the issue normally, as long that the reference qualifiers are properly defined in the platform. You can call javascript conditions on reference fields, but they are not dependent on other input fields or variables, they are dependent on conditions or queries on the platform (so backend not ui interaction) 

I hope this helped. 

Been fighting this one and just discovered the "Use field values for reference lookup" toggle that appears on the Action Item when Type is Script. Toggling this ON, displays a Set field values section below the Execution script.
Here, simply map the field your reference depends on.
In my case, I needed to filter Contacts based on the selected Account. Then I just set Accout > {{Input:i_account}} 

Hope that helps others bumping into this-

I have been fighting with similar issue as well. But unfortunately it does not work for me.
Are you aware if the conditions attribute for the input can be used as a reference qualifier in the mobile app builder. It works when i hardcode the sys_id of parent field however I am not able to figure out how to use the other input field as the variable . I tried input.field_name but it doesnot work.