After I won my game in a team match, my rating goes down from 1911 to 1887, I just can't understand why?

what was your opponents rating?  that figures into the formula

This is not important - you can't lose rating by winning games.

I checked the game and his opponent's rating was 1673, but it shouldn't matter. You're rating should never go down if you win (or up if you lose).

Yes that it pretty weird

maybe u lost a game and didn't noticed.

or perhaps it's a bug

Never a win looses points, I think that you should report to chess.com under the help and support at the bottom of this page as this is a real anomaly.

Just a thought...

How many games were you playing simultaneously? If you have recently lost games (or any since you started the match), your rating would've gone down from them at the same time as going up for the actual win. That's the only non-bug-related thing I can think of. 

 Thanks to you Sir(Arctic on_Tiger) I have already called the attention of the staff incharged of the rating and it was already corrected/adjusted.

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