I think the Dashboard > Opponents > Total Won column is incorrect.
I’ve attached a sample hand history and screenshots that demonstrates this.
In my example, here’s what we see:
(A) Albert’s “Total Won” vs Brian = $0.42
(B) Brian’s “Total Won” vs Albert = $0.68
I would expect that A roughly equals the inverse of B (with only Rake accounting for any differences).
I’ve highlighted what I think is the bug. There’s a hand where both Albert and Brian lose money in a pot that “Ernie” wins. But in the aggregation for Albert-vs-Brian and for Brian-vs-Albert, their respective losses to Ernie is incorrectly included.
I hope the attachments help make this more clear. Let me know if you need a better explanation of the problem.