RED "Full" Battery Icon in Menubar?

[cxminer]

Same thing happened to me. I just toggled "Show Percentage" off and on and colour changed to black.

 

[harshitjindal]

Let battery run into the red (below 25%). Put the computer to sleep. Plug in the power cord. Let it charge. When you wake from sleep it will be red and 100%. Just a rendering bug, happens to me all too frequently. Battery status is "Normal" and the red goes away with the next visual update.

Funny how this bug still exists in 2017

 

[justperry]

Yeah, it still happens on High Sierra, mine just did after the battery was dead last night.
I put my MBP to sleep yesterday when it got down to 5%, I forgot to charge it for a couple of hours, then connected it last night, when I took it of the charger this morning and pushed the on button it took long to awake.
I pushed the on button once more and the logon screen appeared.
After it logged on the red battery icon appeared.