After looking more closely at the area where Soli Deo Gloria 6 came down early on Sunday morning (~3:30am EDT), I think it is likely that the payload did, indeed, come to rest on the ground.
What brought it down? Probably frost - a problem which also plagued Vin Lally's low altitude superpressure balloons back in the '60s and for which no solution was ever found.
The frost would have melted into dew by mid-morning and then, as it evaporated, the balloon would have been able to rise again. The much faster - and earlier - descent on Sunday evening was undoubtedly due to actual loss of gas through pinholes in the envelope. The flight was over by this point, frost or no frost.