“Last activity recorded on {$date}” is not using the date_format_short set in config.inc.php.
It seems related to the locale chosen (and the browser used) as I don’t get the same result with the English OJS interface (Chrome & Firefox) :
Last activity recorded on 11/19/2019
as with the French OJS interface (Chrome & Firefox):
Dernière activité enregistrée le 2019-11-19
Not to say that with Internet Explorer I get:
Last activity recorded on Invalid Date
Dernière activité enregistrée le Invalid Date
My config.php.inc. reads:
date_format_short = “%Y-%m-%d”
locale = fr_CA (I also tried to set it to en_US but it didn’t change anything…)
Related post : Last activity recorded on Invalid Date - #2 by drugurkocak