The same is observed on ZTE MF283. It only shows "Signal strenght" (which is supposed to be RSSI) and # of signal bars are changing independently. Probably it depends on the current modulation scheme. Higher order modulation will indicate lower SNR under the same conditions. I frequently get faster speeds when 3 bars are displayed as opposed to 4 bars (as it should be).Interestingly, I also think that the "signal bar" display on the B593 includes a dependence on RSRQ. On my own device, I have seen situations where even with high signal strength (RSSI > -50dBm), an RSRQ below -6dB (eg -7dB) on LTE shows only 4 bars. I'm interested to see if the E5186 shows the same behaviour.