Beckford appeared unhappy and refused to shake Grayson's hand upon leaving the pitch before heading straight down the tunnel.
The Whites chief expressed his disappointment at the front man's reaction and confirmed he would deal with the issue.
Talks were held on Monday morning and Grayson is confident the matter can now be laid to rest to enable the League One leaders to focus on the Boxing Day game against Hartlepool United.
"We had a chat first thing on Monday," Grayson told the club's official website. "Jermaine explained and apologised for his actions which I fully accept. I made it clear that I don't need it to happen again and he's bought into what I've said. It's been put to bed now and I expect to see Jermaine in a Leeds shirt on Boxing Day looking to knock the goals in over the Christmas period."