If you go to forum logs in ACP, having no logs, an error box is displayed saying:

No log entries for this period.

First off, I have not picked any period. Secondly, you can try to open a log with some entries, search for a keyword that doesn't exist, and again, the same error is displayed, however there are some entries for given period, but search limitation made them not to show.

I suggest removing the second part of the string, so that it will just say:

No log entries.