Without knowing for sure, it does sound like rollover - the below might help you more, look and see if it lines up, it certainly sounds like it does. (a quick internet search)
Every day at 5pm New York Time( 23:59 to 00:01 Server time) you will note that our platform will have a blackout for 2 minutes due to rollover. In the Global Forex Markets this is widely known as ‘End of Fx Day’.
_During the rollover time, all the large investment banks around the world reset their systems and prepare for the next trading day.
_Please note that around the rollover time spreads could be widen and big spikes or volatility may occur due to the low liquidity.