Ok, that’s definitely unusual. I’m not sure if it’s related to the similar problem you had found in the forum — do you have a link to it? I see one that was similar, but I’m not sure it’s the same issue.
It may be that your host restricts writing files in an unusual way, but it’s hard to tell. Just to confirm — do you know what OS the host is running? Falcon should work with just about any type of linux, but there may be unusual issues on Windows hosts.
It might also be something to do with the contents of the file. Can you enable Falcon temporarily, then get a copy of the .htaccess, and switch back to basic caching again? You can paste the contents of the file on pastebin.com and give us a link here — but make sure to take out sensitive information (if any).
When you found the blank .htaccess file, did you check the file size, to see that it is 0 bytes? It’s possible for there to be a lot of empty lines to make it look blank, but I haven’t seen Falcon cause that. Some hacks may do that, but I don’t want to jump to conclusions.
One other item to check is the site’s error log — if something stopped Wordfence from writing the file, there’s a chance that there will be a clue there. Usually the file is error_log or error.log, but the location varies by host. Sometimes it is in the root of the site.
If you don’t want to test it again, since it could stop the site from working overnight, I understand — leaving Basic caching enabled should work in that case.
But if you want to test it overnight again with Falcon enabled, can you save a copy of the .htaccess file if it isn’t 0 bytes? And can you note the date/time listed on the file, to see if it coincides with any blocked IPs?
-Matt R