Minimum Mass for Brown Dwarf to Planet

Unless I'm reading this wrong, the minimum mass to still be a brown dwarf (with solar metalicity) is 51.48(+0.22/-4.00) Mj
Way higher than 13Mj.

New constraints on the minimum mass for thermonuclear lithium burning in brown dwarfs
https://arxiv.org/abs/2110.11982

As far as the dividing line between planets and brown dwarfs is concerned, wasn't it the deuterium burning limit that was of importance?

In any event, I've begun to suspect that it might be better to divide the two categories by formation mechanism rather than a fusion limit, though I recognize that means there will be an overlap between the two categories in mass.