Ok, I think the issue come from the ", " in your options value. When you try to populate the default value with “abc, def” the multiselect will consider that you want to submit 2 items: “abc” and “def”.

I didn’t find yet how to enter as default value an option containing comma.

But there is a workaround. Create an option set with the list of options and use dynamic instead of static choices. Then call the right option in the default value calling all [option set]:filtered.

See example:

Or just use another separator in your options names :slightly_smiling_face: