Can someone tell me what I'm doing wrong when I reply to a thread and there is a line thru the last part of my post and signature?? Thanks

thats to separate the post from the signature

Cougars: Thanks for the reply, but that is not what I mean. I sometimes get a line right thru the text and signature. I have a post now on bowhunting forum on the thread "the enemy within", 2nd post of mine has the problem displayed. It happens every once in awhile and I have no idea why.