Importing array to ACF checkbox field

My user profiles have a checkbox-type custom field (ACF) with two checkboxes.
I can successfully import the field values when it is a single checkbox.
Profiles with both boxes checked end up having no box checked after import.
I have tried separating them in the following manners
value1,value2
value1, value2
value1|value2
Nothing works.
What am I missing