Why did my SPX options combo Stop order get triggered outside RTH?

The ticker symbol for S&P 500 index options is SPX. After entering the ticker select Options followed by the desired contract from the option chains window.

SPX index individual options trade from 09:30 EST to 16:15 EST, but also during extended hours (overnight) from 20:15 EST to 9:15 EST…

If you are subscribed to real-time US Stock Option market data real time Bids and Asks will display starting around 09:28 EST, or just a few minutes before the 09:30 EST opening. Any Bid/Ask prices before 09:28 EST or after the regular market's daily close will be indicative of the last Bid/Ask displayed. Remember to carefully check any US Stock Option order you create overnight when the contract is not actively trading. If you do create a US stock option order overnight, be sure to check your Limit Price during that pre-open session from 09:28 thru 09:30 EST as Volatility and Time Decay can greatly impact option prices as compared to the previous day's close…

SPX and VIX index options trade from 09:30 EST to 16:15 EST, but also during extended hours (overnight) from 20:15 EST to 9:15 EST.

Settlement…

The ticker symbol for CBOE Volatility Index options is VIX. After entering the ticker select Options followed by the desired contract from the option chains window.

VIX index individual options trade from 09:30 EST to 16:15 EST, but also during extended hours (overnight) from 20:15 EST to 9:15 EST…