Hi spinola,
It's not uncommon for spreads to widen during volatile periods such as economic news releases, rollover, and the weekend open.
Pricing on the platform is set by competition from liquidity providers. Each liquidity provider streams through a direct feed of executable buy and sell prices to FXCM. FXCM's Price Engine selects the best buy price and the best sell price, which result in the best available spread.
The chart you posted isn't clear enough to tell symbol traded or the time period. If you can please let me know I would like to check on this on my side.
Jason