I'm getting errors during multitrack recording live to SD card (Studiolive 16 series III)

Ive been successfully recording live shows multitrack (capture 2) to SD card (Sandisk 30 gb microSD recommended by sweet water) with out any problems until recently. After every show I move the folder off card to my laptop. I'm arming 16 track and LR tracks. Its been working flawlessly until last 2 shows. During gig, I look down at the recording screen and instead of green icon its showing red with 5 or 6 errors (90 min recording). I didn't fill card all way. Speed test checks out. Haven't upgraded or changed anything. Just not sure why I'm getting the error messages recently.