[Bug Report] The since date of "git log" will have influence on the until date of it.

The since date of "git log --since" will have influence on the until 
date of it.

How to reproduce?

 1. clone this repo https://erol.kernel.org/lkml/git/8/
 2. run "git log --since="2020-05-30" --until="2020-06-02"", it won't
    output anything
 3. change the since date to 2020-05-29: run "git log
    --since="2020-05-29" --until="2020-06-02""
 4. it will output the commits in 2020-06-02 (The until date)

Why would that happen, I just change the since date from 2020-05-30 to 
2020-05-29, why it suddenly output the commits in 2020-06-02?

-- 
BR,
Lei