Hi @roi
I’m not sure what happened, but a lot of things can happen in two years of time span. It’s possible the issue came from ACF, but it’s also possible that the issue came from WPML itself.
If the issue can be solved by re-saving the post, then I suggest you do that instead. Re-saving the post mostly will save the required data that is not generated back then.
Also, could you please make sure that you have followed the guide here: https://www.advancedcustomfields.com/resources/multilingual-custom-fields/.
Please make sure to backup your site before doing that.
I hope this makes sense 🙂
