wireless keyboard batteries dying fast

My wireless Apple keyboard (Model # A1314) is draining AA batteries very fast lately. This started happening over the last few weeks. In the past my rechargeable batteries lasted for 3-4 weeks between charging now it's 2-3 days before I get a low battery warning. Also in the past my keyboard and mouse batteries would usually run low around the same time, now my keyboard battery level is low while my mouse is still close to fully charged.

I have 12 fairly new rechargeable batteries that I rotate through the mouse and keyboard so I do not think the batteries are the issue. Wondering if it's the bluetooth indicator in macOS (v10.13.6) or a recent update?