Oxygen Builder has a demo of their software on their website that I was just tinkering with. I added a text field, and a FontAwesome field to a blog post, and gave them both some values.
I set up Oxygen to output those two fields in their template editor. The text field showed up, but the FontAwesome field said “No data for field”.
I am guessing this is the same thing you are seeing?
I am not sure what Oxygen Builder is doing behind the scenes to make their builder compatible with ACF. I wonder if they had to code in support for each of the field types, so this third party field type is not supported? Just guessing here.
If you have any support/contact with them it would be helpful to loop them in here as they will understand better the intricacies of how their plugin works with ACF fields. If they have recommendations that need to be implemented on my end to make my plugin compatible with theirs am open to that.