Google groups searching preview having inconsistency between preview and actual page

Here's the thing:
I happened to search a specific word in the search box on the Google Group https://groups.google.com, (already with the "all groups and conversations" option).
Then I found the issue like the title described here.

• First I just searched the word which is "博德之门".(Video game's name)
• And I clicked into the first result message(in "cn.comp" gorup), which I supposed the message of the actual page should be like the one of the preview line itself. As picture 1 and 2 shown.
• But it is not. Instead, it directly jumped to another conversation page, which I never expected, as picture 3.
• Then I checked the "correct" page of the unexpected, by using the "copy link" button on the message's right, as in picture 4.
• I also tried to found the expected page(matches the preview one), as piture 5.

I hovered my mouse over the link, as you can see in pictures 2 and 3. There is consistency between the link itself and its content, but inconsistencybetween both the link itself and the content with the preview.

1_Result's_preview1
2_Result's_preview2
3_The_unexpected_page_of_jump_link
4_The_unexpected_page's_actual_url
5_The_expected_page's_actual_url

I noticed that,

1. the URL in picture 3 is not exactly locate to the message itself, and even replace them with any random content any length strings, it'll still direct to here, the page, which I think is decided by the /c part 11-bits strings.
2. On the other hand, entering the 'correct' URL (the correct 12-bits strings after /m) will turn the bar on the left side of the page blue, something that such previous attempt didn't achieve.
3. I assume the direct cause is the message locator /m went the same, so leads the problem.
4. So I examined the other group as well---"cn.test" in this case, it matches my assumption in 3, too.

So I suppose that's the case, yet I wonder like this:

I think there are two appropriate questions, whether my direct cause opinion is right, or Why is that so? Is that a BUG? If so what should I do? or?

Any suggestions would be helpful regarding this:)

P.S. I've searched the google and super user questions and the google group manual, yet no answer.