Buchanan et al.'s even-order conjecture for odd covers

Let $b_2(n)$ denote the minimum cardinality of an odd cover of the complete graph on $n$ vertices. Let $k\ge2$ be an integer satisfying $k\equiv2,3\pmod4$.

Buchanan et al.'s conjecture. For such $k$,

$$b_2(2k)=k+1.$$

This conjecture specifies the remaining asserted values in the even-order case of the odd-cover problem and was confirmed independently by Buchanan et al. and by Leader and Tan.