Respected koehmstedt, you are not forcing anyone to reply. It is an Open Source Forum and the problems are solved by helping each other.
Regarding the body of your website's post (that was the main topic), #comments will browse down directly to the comments, it can not vanish the texts, you are right.
Example on your own website (normal) :
( Hash with the div's name directs to the intended portion of webpage, like
#respond will directly make you to go to reply form. There is no rocket science behind it. It is a simple HTML function.)
But it is happening with your some selected posts (vanishing texts). That means some plugin, (possibly a comment plugin) is conflicting with PHP function to execute.
I said the above way to test throughly.
Another way is to deactivate Greg's Threaded Comment Numbering Plugin that you are using (I am not sure if there are more comment plugins installed in addition). It might solve the problem. It is actually adding pagination to comments and probably due to a bug, that odd behavior is being triggered.