President Biden on Monday wished Vice President Kamala Harris a happy birthday, while calling her "a great president," a line that some online assumed was another gaffe, which has become synonymous with his administration. 

"Happy Birthday to a great president, we know your mom is always with you," President Biden said while acknowledging Harris' birthday was on Oct. 20. The remarks came during a White House event to celebrate Diwali. 

He also joked that Harris "turned 30." She is 58 years old. 

Biden Kamala Harris gaffe

President Joe Biden speaks after inviting two children on to stage during an event to celebrate Diwali, in the East Room of the White House, on Monday. Vice President Kamala Harris, left, and first lady Jill Biden, right, look on.  (AP)

Biden has called Harris the president at least two times prior to Monday. 

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In January 2021, he referred to "President Harris" during remarks on voting rights.

He also called his vice president "President Harris" during remarks in South Carolina in December 2021. 

In March, he called Harris the "first lady" while talking to reporters. 

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"We've had a little rearrangement of whose on the stage because of the first lady's husband contracting COVID," he said at the time. 

Biden was referring to Doug Emhoff, Harris' husband, who had just tested positive for COVID-19.

Vice President Kamala Harris delivers remarks and President Biden signs an Executive Order on Project Labor Agreements, which will improve timeliness, lower costs and increase quality in federal construction projects in Upper Marlboro, MD at Ironworkers Local 5 on Feb. 4, 2022. (Photo by Kyle Mazza/Anadolu Agency via Getty Images)

Vice President Kamala Harris delivers remarks and President Biden signs an Executive Order on Project Labor Agreements, which will improve timeliness, lower costs and increase quality in federal construction projects in Upper Marlboro, MD at Ironworkers Local 5 on Feb. 4, 2022.  (Kyle Mazza/Anadolu Agency via Getty Images)

Most recently, he was criticized when he called out a recently deceased congresswoman during a White House event in September. 

"Jackie are you here? Where's Jackie? She must not be here," he said, referring to Rep. Jackie Walorski, R-Ind., during the White House Conference on Hunger, Nutrition and Health.

The White House later said the president had misspoken during the conference when he seemed to look for Walorski around the room.

White House press secretary Karine Jean-Pierre brushed off criticism of the remarks, claiming Walorski had been "top of mind" for Biden. 

Biden has a history of gaffes but has referred to Harris as president on a number of occasions.  

In December 2020, after being elected president, Biden called Harris the president-elect during a COVID-19 briefing. In March 2021, he referred to Harris as "President Harris" while touting a vaccine rollout.

Months later in December, he said it again at a speech at South Carolina State University and during a Jan. 11, 2022 speech at the Atlanta University Center Consortium. 

"Last week, [Vice] President Harris and I stood in the United States Capitol to observe one of those ‘before and after’ moments in American history: January 6th insurrection on the citadel of our democracy," he said. 

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On May 13, Biden again called Harris the president during remarks at the U.S.-ASEAN Special Summit.

"The Indo-Pacific is an Indo-Pacific that is free and open, stable and prosperous, and resilient and secure.  It’s what we’re all seeking.  And that’s why I asked [Vice] President Harris to travel to the region last August," he said. "And that’s why, last October, at our virtual summit, I announced $100 million to support — for programs to strengthen U.S.-ASEAN cooperation."