Does the theme use ACF? What version does the theme use? If you have the same input names and IDs then it must be using ACF for it’s fields? Seems strange that they would share IDs because the IDs in ACF are related to the field keys, unless the shared IDs are something that you’re entering. First, you can’t have both versions of ACF installed, so you should check that. If that’s not it then you’ll need to rename your fields and if the keys are really duplicated then you’ll need to delete those and recreate them so that they get new field keys. Field keys being duplicated would be rare since the keys are based on the UNIX time that they were created.
