My assignment rule is not getting applied to catalog task.

[Apex Predator]

I have a catalog item with a few fields. One of which is a select box called 'Problem Category'. I want to populate the assignment group of the task based on the problem category I select while creating the request.
This is my assignment rule.

This is my assign to field:

This is my catalog task with empty assignment group:

One think I noticed is, in the catalog task, when I save the form after I open it, it is assigning the group. 
But I need it to be assigned the first time I open it.
Any help or alternatives would be highly appreciated.
Thank you!

[Alok Das]

yes, even I will also not recommend to hard code but you can save value in Property and call the property with the script gs.getProperty('property.name'). So, whenever you need to modify there will be only property value change not the workflow modification.

However, I see that your issue is resolved so that's great.

[Apex Predator · Accepted solution]

Assignment rules are the way to go. After a lot of trial and error, I was able to get my assignment rule to work. I just had to make the variable in my catalog item 'Global'.

[Alok Das]

Is there any specific business requirement that you are trying to achieve via assignment rule?

Why don't you assign within the catalog task activity script? Something like below:

if (current.variables.variable_name == 'value_of_the_choice') {
    task.assignment_group = 'sys_id_of_the_group';
} else if (current.variables.variable_name == 'value_of_the_choice') {
    task.assignment_group = 'sys_id_of_the_group';
} else if (current.variables.variable_name == 'value_of_the_choice') {
    task.assignment_group = 'sys_id_of_the_group';
}

Kindly mark my answer as Correct and Helpful based on the Impact.

Regards,

Alok