Env:  4.20.0-0.nightly-2025-08-12-153542

Steps:
1. Go To Observe > Metrics

2. Enter into query input: histogram_quantile(0.99, operation:etcd_request_duration_seconds_bucket:rate5m) (I inspected from API Performance > etcd Request Duration - 99th Percentile)

3. Select Units: Bytes Decimal (kb, MB), Bytes Binary Per Second (KiB/s, MiB/s), 

4. Verify Y axis for both units

Result: It is showing undefined concatenated.