Version: ACF 5.8.9
Case:
Repeater field with start and end date.
This is the setting

Problem:
saved dates jump one day back.
example: select friday april 24 and save the post.
output is thursday 23
This is a big issue!
It gets even more weird, look at the month of the date picker and the corresponding source code

functions.php only related time stuff is the following code
date_default_timezone_set('Europe/Berlin'); // Lokalzeit
setlocale(LC_TIME, array('de_DE.UTF-8', 'de.UTF-8'));
searched the forums and removed “date_default_timezone_set” from theme.
checked the rest of the setup. seems to fix the problem.
Hello,
Same problem. Removed โdate_default_timezone_setโ but not fixed for me.
Edit : The server is not on ‘UTC’ and I can’t modify that.