Calculating Joined Fields - Hosted and SQL View

[CESPEDESLUISITD]

I am using ArcGIS Pro 2.9 and I have done the following in Model Builder:

Connected to a SQL view

Connected to a Hosted table

Performed an Add Join to join both tables (the other join creates a permanent join which I dont need)

So far this works and the join appears.

Then, I use the Calculate Field tool to calculate one field on the hosted from the SQL view.

I get the error that I cannot use SQL unless its a feature service. Fine, use Python or Arcade.

But when I open those, the reference to the view fields looks like this

Then, when I try to enter the expression, I get an error

I cant get passed this.

Why would it ask for the datasource if the data source is already there and the data is already joined?

Is it the percent sign? I tried removing it but it doesnt work.

I cant find any documentation on this.

Thanks everyone.

[CESPEDESLUISITD]

Apparently, if I ignore the error message and continue, still works. It says invalid but still allows me to use the reference.