-snip-
Luckily, hosseinimr93 figured out where the problem is and that won't be necessary any longer. All we have to do now is pay attention to the number of empty spaces before the link in case of an edit. It's possible not to notice two empty spaces preceding a link, but it becomes improbable you won't see 3, 4, or more. So if a link suddenly turn unclickable, it's an easy fix.
When editing the post, you can do that by paying attention to the number of empty spaces before the link. However, if there are many link URLs, fixing them will be pretty troublesome.
-snip- Anyway if it's a bug, it's a bug that can be fixed by the poster using a URL tag.
I prefer to use the URL tag on the link URL when creating a post so that when I want to edit the post, I don't have to pay attention to the blank spaces one by one because the link URL has automatically become a hypertext.