During the 16th frame of Maflin’s win over David Gilbert in the first round, the former gave the cue ball the middle finger after his bid to secure 147 maximum ended on the penultimate red.
A tricky pot resulted in the cue ball knocking the yellow out of position when he was on course for a maximum.
Maflin let out his frustration by putting his middle finger in the direction of the cue ball as referee Tatiana Wollaston handed him a warning.
“I have to warn you – the next one, you lose the frame,” she said.
Maflin insisted: “I meant nothing by it – it was purely aggression being taken out on the cue ball.
“I felt like I’d worked really hard to get into that position… and when the white hit the yellow, it was just one of those reactions.
“She [Woollaston] was whispering and I thought she was telling me to tuck my shirt in, but she told me she had to warn me for the gesture.
“I wasn’t quite with it at that stage.”
Eurosport commentator Dominic Dale apologised on air to viewers for any offence caused.
World Snooker have since confirmed Maflin will not face any further punishment beyond the referee’s warning.
Meanwhile, Ronnie O’Sullivan breezed through to round two of the Championship with a convincing 10-1 win over Thepchaiya Un-Nooh.
Speaking after the first session, O'Sullivan said: "In a way no crowds has helped getting in and out of the venue, that has been a lot less hectic.
"I had voiced concerns about the crowd, but this isn’t point-scoring – common sense prevailed.
"We have been told for the last four months to have no gatherings and especially if you are indoors. Then to say you would have a crowd indoors went against what everyone was saying.
"I didn’t understand it, but I think the right decision has been made and I feel a lot safer."