I got an answer on my post which solved it for me which I believe will solve it for you. Because it seems that Twitter returns a URL that points back to a post when the post/tweet is truncated, you need to get the un-truncated version.
To do this, you need to use a parameter called “tweet_mode”, see the upcoming changes to tweets documentation.
Basically, you need to supply “?tweet_mode=extended” to whatever API call you are using to get your tweet. When you do, you will receive the full tweet without truncation which in turn makes the URL in the tweet be the one you want instead of just pointing back to the tweet.