executable script /etc/cron.daily/logrotate has in it, amount other things, the command:
  /usr/sbin/logrotate /etc/logrotate.conf

/etc/logrotate.conf has in it, among other things
  include /etc/logrotate.d

/etc/logrotate.d/syslog-ng has in it, among other things:
  /var/log/remote/*/*.txt
  {
        rotate 8
        maxage 30
        daily
        missingok
        compress
        delaycompress
        postrotate
                invoke-rc.d syslog-ng reload > /dev/null
        endscript
  }

That was set that way yesterday just before noon.

An example directory listing for /var/log/remote/10.128.0.3/log.txt shows only
  drwxr-xr-x  2 root adm      4096 May 26 11:49 ./
  drwxr-xr-x 24 root adm      4096 May 26 23:10 ../
  -rw-r--r--  1 root adm 456943474 May 27 14:55 log.txt

And finally, log.txt in there has lines covering the period:
head -n 2 log.txt && tail -n 2 log.txt
  May 26 11:38:02 10.128.0.3 %ASA-5-304001: 10.134.0.104 Accessed URL 108.168.240.194:http://tags.[snip]
  May 26 11:38:02 10.128.0.3 %ASA-5-304001: 10.134.0.104 Accessed URL 98.139.225.42:http://ads.yahoo[snip]
  May 27 14:56:54 10.128.0.3 %ASA-5-304001: 10.144.0.76 Accessed URL 98.139.199.205:https://98.139.199.205/
  May 27 14:56:54 10.128.0.3 %ASA-5-304001: 10.168.0.62 Accessed URL 23.74.9.136:http://crl.microsoft.[snip]

/var/lib/logrotate/status contains a line for the above sample directory:
  "/var/log/remote/10.128.0.3/log.txt" 2015-5-27-6:0:0

I don't know how to interpret the "-6:0:0" in the line above.