EX6120 Extender loses configuration when unplugged

I have an EX6120 Extender.  Was working fine for the last 4 months.  Then I upgraded firmware to V1.0.0.54_1.0.34.  Ever since then the device will lose the configuration information about my router and network if the device is turned off or unplugged.  I have done resets and downgraded the firmware to the previous version, but it seems to make no difference:

- I plug the extnder in to the power close to my router (as per installation instructions).

- Re-configure the extender for my network.  

- It works fine; anything can connect to it.

- I unplug the extender and move it to the area where I need it.  When I plug it back in, it does not connect to my router.  Based on wifi signal tests, it broadcasts a weak radio signal.  This is an area where it has been plugged in for the last four months and was working fine.

- Even if I move it to another plug in close proximity to my router, it will not reconnect after I plug it back in.

Does anyone have any thoughts?