How to create an autocomplete field using a process (Array)List?

Hello,

I currently have problems trying to use an ArrayList (which was filled with LDAP names before in my process) as an Autocomplete field "Available values".

I can import without problem my ArrayList, called listCommonNames. For this, I am using different variables :

1. taskId

2. taskJSON which is an External API calling ../API/bpm/task/{{taskId}}

3. caseId which is a JS expression return $data.taskJSON.parentCaseId;

4. Then I import my ArrayList with ExternalAPI ../API/bpm/caseVariable/{{caseId}}/listCommonNames

5. After that, I just have to add listCommonNames.value in my Autocomplete input.

BUT, I think that my Java ArrayList is "casted" to a simple String. Indeed, when I use the autocomplete input, it purposes me every letter in my ArrayList!
For example, if my ArrayList contains [toto, titi, tutu, tata], it will purpose me t, o, t, o, etc... So I currently can't have an autocompletion with complete names...

Here is the JSON object when calling my Arraylist (with fake names) :

{"description":"","name":"listCommonNames","value":"[Services Generaux THVN (Rennes), Direction Generale, Tarot Gael, Jerome Francois, Melanie Etienne, Florent Beaupre]","case_id":"1017","type":"java.util.ArrayList"}

I think the problem is coming from the value is between " "...
Do you have a solution to import an ArrayList (also tried with Map), please?

Thanks for your help!