Unable to create many-to-many relation between existing subform and form

Unable to create many-to-many relation between existing subform and form

Hello,
I'm trying to create a many-to-many relation between existing subform and form following this guide: Bidirectional relationship between main and sub-form | Zoho Creator

Here's the structure.

Form 1: Tasks
- Task name (single line field)
- Steps (subform)
--- Step 1 name (Single Lookup field sourcing items from Form 2: Steps)
--- Step 2 name (Single Lookup field sourcing items from Form 2: Steps)
--- etc.

Form 2: Steps
- Step name (single line field)

I'd like to create a bidirectional relation between "Steps" and "Tasks".

So I do the following:
  1. add a Multiselect Lookup Field to the "Steps" form
  2. select the following criteria for the Lookup Field:
    1. Applications: current application
    2. Forms: Tasks
    3. Fields: Task name
    4. Display format: Multi Select
This is where I stop, as:
  1. I can't see the "Existing relations are found for the selectected form. Enable bidirectional data sync?" message
  2. as a consequence, I can't see the "Existing relations with (tasks)" select


If I go to the Schema builder, I can see no relation exists between the Task form and the Steps form:



If I create a relation from the Schema Builder, then a new "Steps" multiselect lookup field is added to the "Tasks" form.

My goal is to be able to create a bidirectional relation between the line items of the "Tasks" subform and the "Steps" records.

What am I doing wrong?

Thank you