Hello Staudy,
This is not a bug! :),
Basicaly Twitter has been upgraded some settings for post a tweets, so share url is given by you is right! and also exist url is not wrong.
For Example :
If you will try to post a tweets using current tweets url https://twitter.com/?status=hello then it is redirecting to same url that you have given https://twitter.com/intent/tweet?text=ssss&source=webclient.
But anyway thanks for update me about this issue, i will replace the old twitter share url to new one!