I just tried to use the ACF Migrate tool, but after it completed I checked some of the custom post fields, and a number of them were read only. No setting I could see marking them as such, but they were greyed out and you can't actually open dropdowns or type in text fields. Not all the fields were like that, but I didn't see a particular pattern to why some worked and some didn't. Per the instructions on the ACF Migrate screen, since there was an issue I restored a backup and am reporting the issue here. Any idea what might have been causing this?