FX Spot -- Cash Settlement Issue

Folks,

I have created FX Spot transaction (60A, ttype 101) to sell Euro and buy USD with cash settlement in USD. We have a favorable exchange rate so we expect net settlement (gain) accounting entry in USD. Example - Debit Cash and Credit Clearing a/c.

When I run TBB1, system is creating two GL entries and two separate documents: one entry for cash settlement in USD and second entry for Euro amount. Also both entries have same update type FX1031+

My question is why system is creating second GL entry in Euro? How come both GL entries have same update type FX1031+?

Thanks in advance,

Amit