Expression Assistant Test & AppSheet Output are not the same

[ky4tz]

I have a virtual column with values computed through the following formula. Using the TEST feature, I was able to confirm that the expression result is what I need.

However, when I save this and load the table in the app, the values are DIFFERENT. Not only are the values not what I expect, every row has the same value.

I've tried this alternative formula: SELECT(Skill Details[Skill],IN([Row ID],[_THISROW].[Skills][Skill])), but the expression assistant threw an error at me: Error in expression '[_THISROW].[Skills][Skill]' : Unable to find column 'Skills][Skill'

Any idea how I can fix this?