Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> 2. M-x debbugs-gnu
>>    There is no way I can C-s C-j to the second or third candidates.
>>    I normally use debbbugs-gnu-search which is the second candidate.
>
> Better ask this elsewhere, I'm not up to speed on debbugs-gnu.

I am attaching screenshot of minibuffer. 

    1. M-x debbugs-gnu
    2. Immediately cycle with C-s

Cycling may happen internally but the UI presents the "most-is-exact"
always at the head.  This is a definite bug.