Is this charging behavior common to all charging banks? Is there a fb loop? How does the Teric sense that it's been charged by a bank and not a transformer?
I believe the process is that the Teric gets to 100% and stops drawing power from the power bank. After a few minutes of inactivity, the power bank automatically shuts off.
So, then, even if the Teric sits there for so long that it drops down to 20%, it won't charge up again until you turn the power bank on again.
Side note: On the Teric, there is a setting for Battery/Quick Charge. You should make sure that is set to Off.