It is a hotfix for the situation if the price moves so fast, that aleeert can't place the TP or SL, as the price is over the trigger price. Now with the fix whenever TradingView detects that a trade should be closed, a maket close is sent to aleeert. Than either the TP or SL order is executed, or the market close, whichever if faster. Most probably the TP or SL will be faster, but if for whatever reason it couldn't be placed, the market close kicks in.