As mentioned above, I found the issue after winning the bug catching contest today, my GMT+7, actual time can be seen in the attached file below
So after kicked out of the contest room with first seat winner, I ran to Goldenrod PC and after that, my connection is failed. Then, I see no the item, my caught Shuckle was vanished and Heracross is deleveled by 1 and lastly, I got 2nd seat winner instead of the previous one.....
Please help explaining at least if you couldn't help.