JTo Big Loser SH?

[Poker Cat]

I'm a consistent winner at the 5-10 6-max.
After 40,000 hands, my win rate averages 2.5 BB/100.

Clearly my game still needs improvement, as there are some (non-blind) starting hands in the red in PT.

The biggest loser? Amazingly, it's JTo. By far.
In 385 plays, it's cost me $1430.50, or .37 BB. I've lost in every position, even the blinds. In smaller samples, it's definitely possible to get some strange results, but with this much info something is clearly wrong. But what?

I've reviewed several games in various situations, and can't find anything amiss. I'm not, for instance, consistently losing to pairs of jacks or tens with better kickers. JTo is not a premium hand, but as a group 5 start it's playable in most positions even in a ring game. How can it be such a loser here?

My only thought so far is that it doesn't do well in heads up matches where bluffing is common, because I can't defend (call) with a jack high.

Any thoughts?