I have see nthis issue before with the Canon t3 specifically, with all the info you provided, it is 100% a bad sensor, if you can get the trade back.. I would do so. Other wise, as others suggested having to edit each photo. The sensor replacement is...
So almost 2 years later, has any one got confirmation from Canon them selves that autp mode on this model will not pop flash up automatically?? I have reaed manual, to me it suggests it will show you a flash symbol EVEN in auto mode for you to manual...