This is even true when -criteria=either is set in an attempt to use file size to retry failed attempts. It looks like time trumps size, even for local sync.
# does not retry interrupted downloads, even though local size is different, time trumps size even for -criteria=either
synchronize local -criteria=either -filemask=l_lb_*
One possible fix: set the timestamp on the file when the download is complete. Let it default to 'now', and set to server time when done. This way interrupted/killed sync operations would automatically restart on 2nd attempt. I think this only makes sense for local/remote, not for 'both' where newest file wins.
P.S. It's possible to force size sync by running two sync commands, but it is awkward when file mask is complex.
# this is only here to force re-download if previous download was killed
synchronize local -criteria=size -filemask=l_lb_*;l_lc_*;l_lp_*;l_mw_*;l_pg_*
# do normal sync - by timestamp
synchronize local -criteria=time -filemask=l_lb_*;l_lc_*;l_lp_*;l_mw_*;l_pg_*