My question is:
When it says "delete the acfml_field_name_patterns key", does it mean to delete the option_value in the DB ? The option_ID ? Or maybe the whole thing ? Can you please be a bit more specific ?
Please delete the whole key by clicking on the Delete button in your screenshot (Suprimmer in your language).
Let us know your results once done, and always before making any changes recommended by our team or another third party have a working backup in place.