How to Pass Javascript number array into bubble as list

I have a JavaScript workflow (via toolbox, run JavaScript) - in it, I grab a list of numbers from the database (to be clear, it’s a single field from a single row that contains a number list), and transform it into in my script to a JavaScript array to do some processing. Once done, I’m trying to send it into an javascript-to-bubble element.
The variable before I try to pass it, is an array, it has length and data.
I’m passing it to the elements optionlist1, which is set to number, and should be a list as per the name.
But, it doesn’t work. The error I get in the browser console is: Trying to send an invalid array to Bubble.
I’m guessing I need to transform the array back into a bubble friendly list or something, but I can’t find out how.

Can you add some screenshots of the setup?