I just want to add that I've been trying to make a stitch "Back up configuration daily to external server via SFTP" working on a daily basis, and all I would get are some random names, similar to "FRSA5Y~D". If I remove %%time%% tag, and leave only tag %%date%%, name generates correctly. So, to resume:
command
exe backup config sftp fgtconfig-%%date%%-%%time%%.conf X.X.X.X username password
would generate a file with name similar to "FRSA5Y~D"
and command
exe backup config sftp fgtconfig-%%date%%.conf X.X.X.X username password
would generate a correct file name.
I wouldn't know what could be the problem, either it's a bug, or something has been changed in the current firmware version (7.2.8), but CLI command "execute time" definitely gives correct time.