Hello – just updated to ACF Pro v5.0.6 and can no longer save changes made to existing fields – it throws an alert prompt about leaving the page / staying on the page once clicking Update. Clicking update just spins and never saves.
WP v3.9.2 Only a few standard plugins installed – update to ACF 5.0.6 was the only change.
Same here: I get the warning about having entered text and leaving the page, I also get the spinner, but this might be an autosave issue or something like that – I’m ultimately able to save the changes.
Just adding my two cents – something isn’t quite right.