Yellow WP7702 Power LED green blinking


we have a small issue with our Yellow mangoh Board with a WP7702 module:

After some time of successfull / normal operation, the power led changes
from normal white illumination (indicating data transmission)
to blinking in green every second.

Also, we recognize, that the transmission stops and we cannot communicate with our device over the linux terminal command line interface anymore.

We have reviewed all available documentation, but could not find any explanation, what this green blinking schema of the Power LED shall indicate.

→ Has somebody experienced this issue before and knows the meaning and root cause of this green blinking power LED?

Thank you very much for your support.

Best regards,

What do you see in device manager when connect usb?