Summary: Date/Time fields are being displayed as UNIX timestamps if added to the ACF Options page, and are also deleted if saved as timestamps.
Reproduced with: WordPress 3.6.1 and 3.7 / ACF 4.2.2 and 4.3.0
Steps to reproduce:
1) Install and activate Advanced Custom Fields (either version listed above), ACF Date & Time Picker (latest version), ACF Options Page (latest version).
2) Add a new field group. Tell it to appear on the global “Options” page.
3) Add a “Date/Time” field to the field group. Tell it to be just a “Time Picker” field. Leave all other settings in their natural state.
4) Go to the Options page and fill out the field with a time.
5) Click “Save Options”.
At this point, you’ll notice that the field, when saved, then displays in the back-end Options page as a UNIX timestamp (which it should not be doing, according to its default settings, which say it should save as a timestamp but be returned as a human readable time). At this point, one of two things can happen:
1) Click “Save Options” again. The fields value then deletes itself.
2) Click on the “Options” page again in the sidebar to essentially refresh the page (refreshing the page directly isn’t reliable because it asks you if you want to submit the form again). Now the field should display it’s correct value (not a UNIX timestamp, something like 1:00 am). However, if you click “Save Options” again, it turns back into a timestamp.
This is the primary issue I’ve had, although I’ve also experienced issues with not being able to reorder fields in field groups that are displaying on the Advanced Options Page, as well as entire fields just disappearing.