I had this false low battery warning/meter freeze problem with my 28II and finally got around to sending it in to Fluke for warranty repair in Everett. I'm the original owner and bought it from an authorized dealer. Fluke was very quick about issuing an RMA and I sent it in.
One month later, I still don't have my meter back. They sent me one notice on May 5, estimating shipment back on May 19. When it didn't come, I called and spoke with customer care three times over the subsequent two weeks, each time promised that I'd get an email from the service lab with an ETA. No email. Last time I called they said that it would be sent on June 6.
This is the second time I've had to send this meter in for repair. The first time was because the display plastic spontaneously (!) developed a 1/2" crack in the lower right corner. Never mind a "torture test"...this meter was never dropped even an inch. It must have been under stress from the time of manufacture. That first repair was reasonably quick.
I've got other meters so it's not like I've been shut down without it, but geez, it's been frustrating. The customer care people I spoke with were all very nice and responsive but they've had no visibility to what was going on and all they could do was send emails to the service lab and "escalate." They seemed powerless to get any real communication or expedite things. The last time I called (when they said it would ship on June 6) they said that the lab told them that they had sent me an email...which they had not. All I got was the original estimate email, but no update. Nothing in my "junk/spam" folder. Who knows.
Your mileage may vary, but this was my experience. I don't know if Agilent would have treated me any better, but in this instance Fluke product and service quality were not as good as they would like you to believe.