"the best bid at the time was $6.40 and your order hit the'
This story keeps changing. That is really problematic.
I've been through a few NYSE arbitrations and this litany of events has become really problematic. A lot will fall to the broker's electronic logs which they are required to archive.
If the order arrived at their server with an 8.85 limit - it just became a good fill. If a glitch occurred at some point, but it hit their server at 8.85. ARCA would have no basis to bust. i would also assume a pop up would have appeared on
@gate's order entry screen cautioned he was trading in ETH session. Assume everybody is telling the truth - the trade log session will be key. Broker produces a log with an 8.85 limit when there was 6.40 bid and this fill will stand.