Firmware 7.7.2 r9663
Sometimes the radio will fail to charge ultimately resulting in the radio turning off if left in this state. More info in this forum thread.
http://forums.slimdevices.com/showthread.php?95022-Squeezebox-Radio-Failing-to-Turn-On!&p=703199#post703199
It is not easy to reproduce this problem on demand but repeatedly unplugging and replugging the power should eventually produce it. It may happen more readily when the battery is only slightly discharged but I cannot be sure.

A bit of forum searching found this
http://forums.slimdevices.com/showthread.php?79039-Battery-doesn-t-appear-to-be-charging
which sounds very similar from 2010

*** This bug has been confirmed by popular vote. ***

Experiencing the same issue. Fails to charge on occasion, then will not turn on.

Is this really a matter of the battery not charging while the Radio is plugged in and operating on power from the wall? Or is it a matter of the plug not properly making contact? If the Radio is ON and operating on battery power, and you plug it in, if the plug isn't properly making contact in the jack, you may not notice that you're not operating on wall power. Or, if it does switch over to wall power when it's plugged in, but that contact is lost, the Radio will revert right back to battery power.

I've had some issues with the plug being loose, or maybe it's a bad internal connection to the jack. If the radio was OFF (usually because it had been on battery power, had been idle and shut itself off) then it sometimes doesn't power back on when plugged in. Obviously, in that case it cannot charge the battery, but I've never noticed a problem with it not charging the battery when it was plugged in.

What's the reason for resolving this 'won't fix' - other than Logitech no longer being the slightest bit interested?

What's the reason for resolving this 'won't fix' - other than Logitech no longer being the slightest bit interested?