Change or bug in the DATETIME_DIFF formula


Hi, this morning it seems that the formula “DATETIME_DIFF(End, Start)” express the result in minutes and no more in seconds as before.
The “Start” and “End” fields are Date fields in ISO format with a 24h date field.

An Exemple:
Start = "2016-07-19 08:00"
End = "2016-07-19 08:30"
“DATETIME_DIFF(End, Start)” = 30 (minutes), instead of 1800 (seconds)

According to the documentation and my experience (as my formula did work until this morning), if the result format is not specified in the formula, it default to seconds.
I tried to specifiy the seconds like that: “DATETIME_DIFF(End, Start, 'seconds”)". It change nothing.

Is it a bug or a change to the formula ?
I have a time tracking relying on that formula and that bug/change has broken everything…


The bug has been corrected (thanks to Alex!).