I have had several episodes when Navigator CGM readings start giving false low readings. These often happen at night but usually it recovers in a minute or two and resumes more accurate readings. But several times it continued to keep dropping and gives very low readings for hours. During these times I tested with finger sticks on Navigator and another meter and get BG levels 100-150 points higher and well in normal or safe levels. Usually these episodes end with a message to replace the sensor after a few hours. These erroneous low readings can be 10-50 % of actual finger stick readings and stay low for hours. I have one on now that started malfunctioning last night and gave erroneous readings for eight hours. Then it started working again and was right on with finger stick tests. When it started working again it jumped from 48 to 225 and finger stick reading at that time was 228. It is easy to guess that the 39 or 26 readings are bogus when finger stick readings are 100 points higher, but not so easy to know that the 123 reading is actually a 248. I find because of these reliability issues I actually test more than I did before the Navigator. Anyone else having this happen?