I answered your query yesterday via email as below.
Are you saying that unmatched bets placed before the market goes in play are not cancelled when the market goes in play or that the bets are actually triggered after the market goes in play?
To prevent bets from being triggered when the market is in play then you must include a reference to cell E2 in you trigger, example below.
=if(and(f5<1.5,e2<>”In Play”),”BACK”,””)
The above example will only place the bet if the back price is below 1.5 and the market is not in play.