The star hooker won his third premiership ring on Sunday night, helping steer Penrith to a dominant 28-12 victory over Parramatta at Accor Stadium.
Koroisau was seen flaunting his three rings - two from the Panthers and one from South Sydney - after the emphatic win, and was involved in the club's celebrations on Monday.
The 29-year-old did cause a bit of a stir however when he mocked his chances of earning a fourth title, with Koroisau set to join the Tigers on a long-term deal in 2023.
“Just to go out on a high like that, it’s pretty incredible," he said.
"I’ll probably do the same thing at the Tigers...[laughs]."
Koroisau's cheeky dig at his next club didn't go unnoticed, with many fans on social media reacting to the comments and some branding it as disrespectful.
Speaking on SEN Breakfast With Vossy and Brandy on Tuesday morning, Hagipantelis said the club would deal with the matter privately.
“The comments have not escaped our attention of course...I suspect that this will be the first subject of conversation this morning," he said.
“Last night, our CEO Justin Pascoe and I both reached out to Api’s manager. The matter has been dealt with and dealt with privately. I’m not particularly keen on giving it too much oxygen this morning.
“As I understand and I don’t know him too well, but Api is a thoroughly decent fella and presents as such.
“I’m sure if he had his time again he might re-think those comments. They were in the spur of the moment and emotions play a large part and perhaps some alcohol as well.
“We’re not going to put a lot of stock into it and we’re very keen on welcoming him to the club as soon as his World Cup commitments are complete.”
Wests will welcome another star from Sunday night's decider, with Eels second-rower Isaiah Papali'i confirming his commitment to the club.
Hagipantelis put to bed any rumblings of a backflip once and for all, and said the Tigers are looking forward to welcoming the Kiwi star after the World Cup.
“This was a storm in a teacup, it has been for quite some time...we’ve refrained from commenting on it because there was no need to," he said.
“We are contractually bound to Isaiah, he is contractually bound to the Wests Tigers and there’s never been any suggestion from either side that they were not going to fulfil their contractual obligations.
“We’ve received assurances that Isaiah will be joining the club as soon as his World Cup obligations are complete as well.
“We gave that story no oxygen whatsoever as well because there was nothing in it.”