The %22 is not trimmed off. It's just shown in its more natural form: a double quote mark.
According to the
rules of URLs, certain punctuation characters in URLs have to be represented in the %xx syntax, where xx is the hex value of the character. Decimal 22 is the value of the ASCII double quote character, so %22 is the URL syntax for a double quote character.
The extra trailing " in
sazivad's post is shown as %22 in the resulting URL. When you quote the post you see the " syntax. It's the same character, shown two ways. If you view the bad post and hover over the link you'll see %22 in the URL. If you quote the post you'll see " in its place. But if you preview the post with the quote (or post it) you'll once again see the %22 form.
It's the same idea as seeing [b]hello[/b] while editing a post and
hello when you make the post. Same information in two syntaxes.
I'll mention, while hoping not to confuse things further, that you can write a URL in a post as either
[url=https://www.macrumors.com]MacRumors[/url] <--- no quote marks
or
[url="https://www.macrumors.com"]MacRumors[/url] <--- matching quote marks
but if you include only one of the two double quote marks your post will be broken.
