its correct.
under wanted status, a plunderer might be atked by other players.

"If this player loses when challenged, he will not lose anything" -> other player attack u and he lose. he will not lost anything. u will also not lost anything.

"if he win, he will got some coins" -> you will lost your coins.

So if u are in wanted and you lost to someone, you should lost 50k coins and they gain 50k coins.
thats afaik hahaha no one atk me yet :p

"this player" referring to the attacker.

if it was referring to the defender(plunderer), they would have said "plunderer" instead of "player" as you can see on all the sentence above.

i think they refer to the attacker not plunderer.
as if it was refer to the plunderer they will write "plunderer" instead of "this player"

well its just my opinion.

yup the translation is abit emm ambiguous..
nevertheless the game is soo good and if can u need to do plunder. its free 150 coupon xD