Trade exit time doesn't match signal tradedwhen

A trade’s entry time matches the open signal’s tradedwhen, but the exit time does not.

Here is a query:

Int64 systemId =
119447297; // TEGJ Trading

TABLE =
from trade in C2TRADES where trade.SystemId == systemId
join openSignal in C2SIGNALS on trade.OpenSignalId equals openSignal.Id
join closeSignal in C2SIGNALS on trade.OpenSignalId equals closeSignal.Id
select new {
entryTime = trade.EntryTime, exitTime = trade.ExitTime,
openWhen = openSignal.TradedWhen,
closeWhen = closeSignal.TradedWhen
};

ops, sorry, i joined the other signal also on openSignalId.
Sorry!