Had something similar happen to me on my 1st IC40 about 10 years ago. Pentair replaced the cell under warranty, but I was still not happy that it lasted less than two years.
Do you have an Easy-Touch or Intellitouch controller? If so, have you checked the diagnostics? If the salt level reading is significantly less than the 3000 ppm from your testing, then it's very possible that it's the flow sensor. I just replaced the sensor on my current unit because it was indicating very low salt (2250ppm). After the replacement, the reading is now 4000 ppm.
If you can get the cell replaced, that would definitely be best. If so, ask the service guy if you can keep the old cell. If the old sensor is still any good, it might make for a good temporary replacement part somewhere down the line. If you wind up having to buy a new cell, try to keep the old one on-hand. Never know if it might come in handy.