On April 27, 2021, Kahl was confirmed by a vote of 49–45, with many GOP Senators absent.[1] He was sworn in the following day by Secretary of Defense Lloyd Austin.[27]
“On April 22, 2021, the Senate voted to invoke cloture (limit debate) on the nomination by a vote of 51–50, with all Republicans in the Senate agains the motion, requiring Vice President Kamala Harris having to break the tie on the motion.”
The vote you are referring to, in which Harris participated, was a procedural vote limiting debate, not the confirmation vote. The confirmation vote was 49-45. Harris did not participate in the confirmation vote since several Republicans chose not to be present for the final vote.