Bentley lost 36-0 at National Conference Premier Division side West Hull in the second round on Saturday.
Around 200 fans made the trip from Doncaster – and despite the result enjoyed the day.
However, the occasion was marred by a video filmed after the match of an individual urinating inside the Bentley dressing room which circulated on social media. The video also showed a door hanging off its hinges.
It is understood the person responsible had been at the ground watching and not playing.
Bentley addressed the issue on social media on Sunday and published another statement on Tuesday, which said: “The individual involved has been suspended, with immediate effect, for 12 months (6 months of which is deferred) from playing for either open age side.
“Unfortunately due to our facilities we don’t have the power to ban the individual from the public arena.
“He has been warned of his conduct as a spectator should he be seen at any game from junior games through to first team.
“We as a club will be supporting him and he will be integrated back into playing on completion of his suspension.
“The individual in question has asked us to release a short statement: “I apologise unreservedly for any distress caused by my actions on Saturday.
“I understand that my actions have put my club in bad light and for that I apologise to all the players and supporters at the club.
“To West Hull again please accept my apologies to all of your players, staff, supporters and anyone associated with the club. My actions were totally out of character and I will forever be regretful of what I did.”
“Bentley and West Hull are still in dialogue regarding a donation to them to be used where they see fit.”
Reflecting on the rugby, head coach Andy Whitfield praised his team.
“They gave it their all and showed plenty of spirit,” he said.
“West Hull were just too good for us on the day but I've got nothing but praise for my players.
“It’s just a shame what happened after the game has overshadowed a momentous occasion for the club.”