As far as I know, you have to correct the errant pass *before* you
cross the s/f line again. At bristol, this can sometimes be hard to
do.
One other thing - since the pace car is a ghost car now, I don't know
if it will slow down if you are blocking the track. Once you are
passed by the pace car while a caution is underway, if you pass it
back, you might get a black flag.
These aren't necessarily bugs as much as they are drivers not paying
attention to what they're doing. Granted, sometimes, the situation
just gets you all confused, and you are bound to make a mistake once
in a while. My personal opinion is that if a driver makes a mistake,
he pays for the mistake, and while it might be reasonable to gripe
about it, calling it a bug in the sim is often a bit over the top.