Heey,
I know this is an old issue, but I write this down anyway for people new to this subject.
This issue has nothing to do with Flow really and it isn't a bug. The logic you try to apply is incorrect and Flows is correct. The Condition action should have a Boolean (true or false) as input. The function empty(variable x) returns 'true' when variable x is empty or 'false' if it is not empty. In your example you want to check if 'Search_for_users' is empty, but you don’t. You check if the value of ‘Search_for_users’ is equal to the return value of the empty(variable x) function.
For example: ‘Search_for_users’ doesn’t have a value (this means it’s value isn’t true or false, but empty). The function empty(‘Search_for_users’) returns true because ‘Search_for_users’ is empty. So what you are asking in your first example is: Is the body of ‘Search_for_users’ equal to the return value of empty('Search_for_users)? NO it isn’t. ‘The body for Search_for_users’ isn’t true but empty. In other words: Is null equal to true --> No it is not.
Your second example DOES work because empty(‘Search_for_users’) returns true to the Condition action. In your first example you compare the body value of ‘Search_for_users’ with the return value of the empty() function, which in turn returns false to the Condition action.
So your condition should be: empty(‘Search_for_users’) is equal to true.
