How do you filter one assets custom field with another?

[KC Wong]

My original goal is much more complex, but since it's not working as I expect I'm now simplifying it to this:

1. customfield_12389 points to Assets schema (no filtering except objecttype = xxx). Single valued. 

2. customfield_12390 will limit its choices to what is selected in cusotmfield_12389.

I set 12390 to use filter: 
objectyype = xxx and key = ${customfield_12389}

The UI accepts that filter as valid, but in the create issue form it will show dialog with message:

We couldn't fetch any objects for this field

Remove attributes that no longer exist in the Assets Custom field configuration filter, and ensure the AQL query is valid.

I tried the following but none of them works. Either UI says invalid placeholder, or error message when using it. 
name = ${customfield_12389.name}
key = ${customfield_12389.key}
objectid = ${customfield_12389.id}

How do I reference another assets field using placeholder? 

[KC Wong · Accepted solution]

It's a typo... objectType. And use label = ${customfield_xxxxx.label}

[Arkadiusz Wroblewski]

Hello @KC Wong 

You can do this by using Filter work scope (AQL) on the second Assets field and referencing the first field using the custom field ID (e.g. ${customfield_xxxxx.label}). This allows the second field to only show objects related to the value selected in the first field.

This is the typical approach used to create cascading Assets fields in Jira Service Management.