There isn't a problem with the offsite investment feature. The feature itself is fine. It's just that RHavar and devans deceived investors by stating a kelly criterion that was 1/2 of what it really was while profiting greatly at their expense.
Can you quote where they stated this?
I think it's confusion between the most a single account can bet in one round, and the most all the accounts together can profit by in one round.
So two confusions: one account vs. all of them, and the amount staked vs. the amount profited.