V Sge is type CBSS/V+E (Close Binary Supersoft Source, V Sge + eclipsing). It shows a range of variations including 3 mag flares, small variations over days and IDV's (intra day variations). There is also a period of |320 days hiding in the data. The pOrb is 12.5hrs which has been decreasing over the past 70 years.
Since 2011 the amplitude of variation has decreased from 3 mags to arond one magnitude.