No, its not hack. Since the new patch, there is a bug sometimes where when you press trade on someone, you crash for no reason. Its happened to me countless times.
It also happens when inviting someone to a guild, duel, inviting to a party, sending a mail, using RP potions while sitting, using an RP potion while charging, turning a monster into candy while it is knocked down, knocking down candy, and trying to scan someone with a scouter.
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