Yes, turtle can certainly pop up with some bars left.
It happened to me in 2013, when it was getting its capacity wrong. With 1 bar it could show turtle for a second and after few meters it would stop without energy. But that will happen to very few i-MiEV owners, because usually the car recalibrates its remaining capacity from time to time. Just when the battery suffers an high rate of degradation is a short period of time (8% lost in 3 months, because of extreme hot conditions and frequent use at high speeds, for example), this can happen.
I´m not the only one that saw this:
hkbob123 - "Hello everyone, I am come from Hong Kong ,my iMiEV is right hand drive HA3W. I have a critical issue that my car apear "turtle" light while the battery status still have 2 bar flashing,I still keep low speed driving then become "battery logo" light and shut down after 200 meter drive,anyone know that issue related to battery or emu program?Thank you very much!" viewtopic.php?f=23&t=2834
Rosacastillon - "The vehicle has indicated overly optimistic mileage that has resulted in my wife being stranded once, at midnight." viewtopic.php?f=23&t=2648&p=23169#p23169
With Rosacastillion, I believe the car was stopping with some bars in the gauge, and a high value of mRR (that's how I understand - "indicated overly optimistic mileage"). He doesn´t say it, but I believe the car showed turtle some seconds before stopping.
Riding an i-Miev since 4/2011 in Portugal, 100.000 kms.