I first discovered empty lines when I copied some files worked with in Apple's TextEdit into an old 3rd party app called Tex-Edit Plus. This was when I first realised TextEdit causes problems. So for the connection files (when I remember) I usually copy into Tex-Edit Plus to find the empty lines & remove. I ended up doing this for the hostiles earlier.
Reason why:

When I used Notepad++ in Win 8 to convert to unix/osx, I noticed at the end of the large hostiles that the first array of the ip address ended up on the previous line with I think it was a (E) or something before it.

Example:
255.255.0/25255.
255.255.128/26255.
255.255.192/27255.
255.255.224/28255.
255.255.240/29255.
255.255.248/30255.
255.255.252/31255.
255.255.25522

This was the first time I ran the operation. An edited smaller version of the hostiles I did a few mins ago did not have the same issue. Converted from CR to LF.
First time, I Selected All before the operation. I suspect that might have caused the problem.
Thanks, I'll check it out.

Though my Tex-Edit Plus effort should also have removed the empty lines in the last update I did several hours ago called V3. (There was a chance I missed a blank line or two.) But it is still in CF & not LF.