That’s strange, could have swore there was a setting on that field at one time. Been a while since I used an image field I guess. If the gallery field is only returning IDs this is usually caused by something else interfering. The question comes up here often, like this one https://support.advancedcustomfields.com/forums/topic/image-field-on-term-returning-id-instead-of-array/
You’re going to need to narrow down where the interference might be coming from by disabling other plugins and possibly switching themes.
