Started auto descend before 15% battery

[BlackTracer]

I have auto-land disabled in the assistant so no message came up asking to RTH. I got first level battery warning at around 23% so I brought it right in front of me to catch. I then looked down and saw my batt level was at 19% but it started descending with sticks centered. I was able to keep it at a constant height with the throttle to finish the catch but didn't expect it to start auto-descending until 15%.

Is what happened normal? It caught me off guard.

Running 3.06