How can you be related with someone on Chromosome X while not bearing same maternal haplogroup?

[oyster]

I am related with this person on 23andme and we only share a segment on Chromosome X, nothing else. Still, we are of different mtDNA haplogroups (I am an H vs his J; also, YDNA I2 vs I1). Sharing on Chr X shouldn't mean same hg?

He is a Romanian too.

[Thrax]

mtDNA has nothing to do with Chromosome X.

Chromosome X, like the other chromosomes can be found in the cell nucleus, while mtDNA is found in the mitochondria of the cell.

[Thrax]

And to make this simpler:
A male gets his X chromosome from his mother.
A female has two X chromosome, one from her mother and one from her father.
So, a male can inherit either his grandmother's or his grandfather's X chromosome.

MtDNA is only inherited from one's mother.