Brilliant, worked straight out of the box, thanks so much!
Well that’s frustrating – definitely due to a conflict with Types, but that fix doesn’t work and there are no errors showing. I’m just going to do without Types as it wasn’t essential in the build anyway. Thanks for you help and pointing that out, I didn’t realise there was a compatibility issue.
Ah right, it’s a select2 field being used to select a page link. Also happened when I tried to allow taxonomy selection via a dropdown.
I’m using ACF Pro 5.4.8 and this happens in Chrome and Firefox (both up to date)