Multiselect/Multiple Checkbox Repeating first value

I have a directory that draws on Advanced Custom Fields for user data. One of the pieces of information members enter that appears in the directory involves selecting one or more checkboxes for certifications they have. I have this set up to show values in a comma delineated list and it used to work fine, but recently (not sure when this happened), if users have multiple boxes checked, the list repeats the first one multiple times instead. If they only check one, the correct one shows up. But if they check two, then it will be whichever one comes first, followed by the same certification repeated. Looks like a bug – not sure if there’s something I can do to fix but definitely need it fixed! Thanks!